; CRC Simulation ; written by Crystal Barchet and Teresa Carrigan, 2004 globals [ original original-message final-answer number crystal generator-list num-yellow realOriginal x y column column1 columnDiv padded toprow botrow dividend lengthG newDividend zeroes pad step praise myDigits generator new-generator doneyet? start-x number-of-digits ] patches-own [ name ] breeds [ divisbar equalbar top divisor digit dividend-all dividend-bit divisor-bit working ] digit-own [ digit-value ] turtles-own [ state tname goname] ;runs setup when program is first loaded to startup setup end ;initializes variables to setup locals [here-y] ca set praise ["You got it!" "Correct!" "Awesome!" "Perfect!" "Right!" "Bravo!" "Splendid!"] set myDigits [ "0" "1" ] set generator-list ["101" "111" "1011" "1101"] set original "" set number 0 set x 0 set y 0 set generator random-one-of generator-list set lengthG length generator ifelse lengthG = 4 ;make a random 8-bit "original" pattern [ repeat 11 [ set original (word original random-one-of myDigits)] set number-of-digits length original set crystal add-space original ] [ repeat 10 [ set original (word original random-one-of myDigits)] set number-of-digits length original set crystal add-space original ] ; create explanation bars at top and bottom ask patches with [ pycor < -25 or pycor > 25] [ set pcolor blue ] ask patch-at 25 34 [ set plabel "Cyclic Redundancy Check (CRC) Error" set plabel-color white set name -1 ] ask patch-at 45 28 [ set plabel "number here" set plabel-color white set name -2 ] ask patch-at 45 -30 [ set plabel "" set plabel-color white set name 1 ] ask patch-at 45 -35 [ set plabel "" set name 2 ] explain -2 "Message Received: " + add-space original + " Generator= " + generator set step 0 set realOriginal original set doneyet? false end to explain [ which what ] ask patches with [ name = which ] [ set plabel what ] end ; clears the black area and the dividend and divisor go to their relatives spots & creates the division bar to step0 locals [ here-y here-x ] set here-y 15 set here-x ( - 20 ) explain 1 "First divide, using the generator as the divisor" explain 2 "Dividend: " + original wait slow-motion * 5 ; creates the division bar cct-divisbar 1 [ setxy here-x here-y set color white set shape "divisbar" set size 7 set tname "" ] ; this is the "spot" where the divisor wanders to cct-divisor 1 [ setxy 42 28 set shape "circle" set color black set label-color cyan set label generator + " " ; set size 0 set tname "moving" ] ; moves the divisor to its spot ask divisor [ wander-to-divisor ] ; this is the "spot" where the dividend wanders to cct-dividend-all 1 [ setxy 46 -35 set shape "circle" set color black set label-color yellow set label original + " " ; set size 0 set tname "moving" ] ; moves the dividend to its spot ask dividend-all [ wander-to-dividend ] repeat length original [ ; creates the top of the division bar cct-top 1 [ setxy ( here-x + 2 ) here-y set color white set shape "top" set size 7 set here-x here-x + 3 ] ] ;] set step (step + 1) end to scroll locals [ turtle-set top-line offset] set offset 15 ask dividend-bit [ set top-line ycor ] set turtle-set turtles with [ ycor < top-line ] ask turtle-set with [ycor > (top-line - offset )] [ die ] set offset ycor-of max-one-of turtle-set [ ycor ] set offset ( top-line - offset - 5) ask turtle-set [ set heading 0 repeat offset [ fd 1 wait slow-motion / 8 ] set ycor round ycor set heading 180 ] end ; if dividend is all zeros, then the message we want to send is all zeros to-report check-for-all-zeros locals [ result ] set result true ask dividend-bit [ if label = "1" [ set result false ] ] if result [ set step 13 ] report result end to bring-down-digits locals [ div-bit-ycor curr-div-bit div-bit-set working-line working-y curr-working done? num-working num-to-bring-down all-zeros? ] ask random-one-of dividend-bit [ set div-bit-ycor ycor ] ifelse not any? turtles with [ ycor < div-bit-ycor ] [ ; first time if check-for-all-zeros [ stop ] set div-bit-set dividend-bit with [ label-color = yellow ] set curr-div-bit min-one-of div-bit-set [ xcor ] while [label-of curr-div-bit = "0"] [ ask curr-div-bit [ set label-color cyan ] set div-bit-set dividend-bit with [ label-color = yellow ] set curr-div-bit min-one-of div-bit-set [ xcor ] ] if count div-bit-set < lengthG [ explain 1 "After dropping leading zeros, there are too few" explain 2 "bits left. Since they aren't 0, there was an error" set step 20 stop ] repeat length generator [ ask curr-div-bit [ set label-color cyan ] set div-bit-set dividend-bit with [ label-color = yellow ] set curr-div-bit min-one-of div-bit-set [ xcor ] ] ] [ ; not first time ; drop leading zeroes ask min-one-of working [ ycor ] [ set working-y ycor ] if working-y < -18 [ scroll ask min-one-of working [ ycor ] [ set working-y ycor ] ] set working-line working with [ ycor = working-y ] set curr-working min-one-of working-line [ xcor ] set done? (label-of curr-working != "0") set all-zeros? false while [ not done? ] [ ask curr-working [ set label-color red ] set working-line working with [ ycor = working-y and label-color != red ] ifelse count working-line > 0 [ set curr-working min-one-of working-line [ xcor ] set done? (label-of curr-working != "0") ] [ set done? true set all-zeros? true ] ] ; count digits in bottom working line, bring down to match size of generator set working-line working with [ ycor = working-y and label-color != red ] set num-working count working-line set num-to-bring-down (length generator - num-working) bring-down-n working-y num-to-bring-down all-zeros? ] end to bring-down-n [ to-y num-to-bring-down all-zeros? ] locals [ div-bit-set curr-div-bit working-line done? ] set done? false set div-bit-set dividend-bit with [ label-color = yellow ] set num-yellow count div-bit-set if all-zeros? [ ; special case here, when num-yellow = 0, CRC = zeros if num-yellow = 0 [ set step 15 stop ] ; add one to num-to-bring-down for every leading zero set curr-div-bit min-one-of div-bit-set [ xcor ] while [ not done? ] [ ask curr-div-bit [ ifelse label = "0" [ set label-color cyan hatch 1 [ set breed working set heading 180 set shape "box" set color black set state "too high" set label-color red ] ] [ set done? true ] ] ; end ask curr-div-bit set div-bit-set dividend-bit with [ label-color = yellow ] if count div-bit-set = 0 [ set done? true set step 15 ;;;;; call a new procedure and stop bring-down-zeros to-y stop ] set curr-div-bit min-one-of div-bit-set [ xcor ] ] ; end if all-zeros? ] set num-yellow count div-bit-set if num-to-bring-down > num-yellow [ set num-to-bring-down num-yellow ] set curr-div-bit min-one-of div-bit-set [ xcor ] repeat num-to-bring-down [ ask curr-div-bit [ set label-color cyan ] ask curr-div-bit [ hatch 1 [ set breed working set heading 180 set shape "box" set color black set state "too high" ] ] set div-bit-set dividend-bit with [ label-color = yellow ] set curr-div-bit min-one-of div-bit-set [ xcor ] ] ask working with [ state = "too high" ] [ while [ycor > to-y] [ fd 1 wait slow-motion / 4 ] set state "done" ] end to bring-down-zeros [to-y] locals [ num-to-kill working-line curr-working ] ask working with [ state = "too high" ] [ while [ycor > to-y] [ fd 1 wait slow-motion / 4 ] set state "done" ] set working-line working with [ ycor = to-y ] set num-to-kill ( count working-line - lengthG + 1 ) repeat num-to-kill [ set curr-working min-one-of working-line [ xcor ] ask curr-working [ die ] ] ask working-line [ set label-color white ] end ; brings the divisor to the right spot under the dividend to step1 locals [ working-line working-y ] explain 1 "Dividing using XOR" explain 2 "Bring down the divisor" bring-down-digits if step > 10 [ stop ] ; brings the divisor under the dividend ask divisor [ wander-to-under ] ask min-one-of working [ ycor ] [ set working-y ycor ] set working-line working with [ ycor = working-y ] ask working-line [ hatch 1 [ set breed equalbar set color white set shape "equalbar" set size 4 set label "" set heading 180 fd 4 showturtle ] ] set step (step + 1) end ; does the XOR to step2 locals [ working-y working-line ] explain 2 "Take the XOR" ask min-one-of working [ ycor ] [ set working-y ycor ] set working-line working with [ ycor = working-y] ask working-line [ do-xor ] wait slow-motion * 5 ifelse check-for-done [ set step 3 ] [ set step 1 ] end ; if this step is reached, it is finished dividing (standard case) ; check for needed padding to step3 locals [ working-y to-y curr-x working-line one-less] bring-down-digits set one-less lengthG - 1 set to-y 14 ask min-one-of working [ ycor ] [ set working-y ycor] set working-line working with [ (ycor = working-y) and (label-color != red) ] if count working-line > 0 [ ask working with [ label-color = red and ycor = working-y ] [ die ] ] set working-line working with [ (ycor = working-y) and (label-color != red) and (label-color != white) ] set curr-x min-one-of working-line [ xcor ] ifelse count working-line = 0 [ explain 1 "Since the remainder is 0, there is no error" ifelse lengthG = 3 [ repeat 2 [ set original-message but-last original set original but-last original ] explain 2 "The original message sent was: " + add-space original-message ] [ repeat 3 [ set original-message but-last original set original but-last original ] explain 2 "The original message sent was: " + add-space original-message ] set final-answer false set step 20 ] [ explain 1 "Since the remainder is not 0, an error has occured." explain 2 "Original message can not be recovered." set final-answer true set step 20 ] end to step13 explain 1 "The message was all zeros, so there was no error" ifelse lengthG = 3 [ repeat 2 [ set original-message but-last original set original but-last original ] explain 2 "The original message sent was: " + add-space original-message ] [ repeat 3 [ set original-message but-last original set original but-last original ] explain 2 "The original message sent was: " + add-space original-message ] set final-answer false set step 20 end to step15 locals [ working-line working-y] ask min-one-of working [ ycor ] [ set working-y ycor] set working-line working with [ (ycor = working-y) and (label-color != red) and (label-color != white) ] ifelse count working-line = 0 [ explain 1 "Since the remainder is 0, there is no error" ifelse lengthG = 3 [ repeat 2 [ set original-message but-last original set original but-last original ] explain 2 "The original message sent was: " + add-space original-message ] [ repeat 3 [ set original-message but-last original set original but-last original ] explain 2 "The original message sent was: " + add-space original-message ] set final-answer false set step 20 ] [ explain 1 "Since the remainder is not 0, an error has occured" explain 2 "" set final-answer true set step 20 ] end to do-xor locals [ one-above me] set heading 0 set one-above turtles-at 0 5 set me self hatch 1 [ set heading 180 fd 6 set label calc-xor me one-above ] end ; this method makes the divisor go to the correct place from the blue bars to wander-to-divisor locals [ to-x to-y n offset] set to-x ( - 24 ) set to-y 14 while [ (ycor != to-y) or (xcor != to-x) ] [ set color pcolor set heading towardsxy-nowrap to-x to-y set n (distancexy to-x to-y) ifelse n > 1 [ fd 1 set heading towardsxy-nowrap to-x to-y ] [ setxy to-x to-y ] wait (slow-motion / 8) ] set tname "done1" set new-generator generator set offset 0 set column 0 ask patch-at -1 0 [ repeat length generator [ sprout 1 [ set breed divisor-bit set shape "box" set color black set label last new-generator set label-color cyan set heading -90 fd offset set offset offset + 3 set state "done1" set botrow 2 set column column + 1 hideturtle ] set new-generator but-last new-generator ] ] end ; this makes the dividend go to the right place from the blue bars to wander-to-dividend locals [ to-x to-y n offset ] set to-x ( 7 ) set to-y 14 while [ (ycor != to-y) or (xcor != to-x) ] [ set color pcolor set heading towardsxy-nowrap to-x to-y set n (distancexy to-x to-y) ifelse n > 1 [ fd 1 ] [ setxy to-x to-y ] wait (slow-motion / 8) ] set tname "done" set label "" set offset 0 set newDividend original set column1 0 ask patch-at -25 0 [ repeat length original [ sprout 1 [ set breed dividend-bit set shape "box" set color black set label first newDividend set label-color yellow set heading -270 fd offset set offset offset + 3 set column1 column1 + 1 set toprow 1 ] set newDividend but-first newDividend ] ] die end ; this procedure makes the divisor go under the dividend when doing the first division step to wander-to-under locals [ to-y to-x cyan-turtles gen-turtles now-x ] set cyan-turtles turtles with [ label-color = cyan ] ask max-one-of divisor-bit [ xcor ] [ set now-x xcor ] ask min-one-of turtles [ ycor ] [ set to-y (ycor - 5) ] ask max-one-of cyan-turtles [ xcor ] [ set to-x xcor ] ask divisor-bit [ hatch 1 [ set breed working set heading 180 set shape "box" set color black showturtle ] ] ask working with [ xcor <= now-x ] [ while [ycor > to-y] [ fd 1 wait slow-motion / 4 ] set heading 90 repeat (to-x - now-x ) [ fd 1 wait slow-motion / 4 ] ] end ; this is the XOR method to-report calc-xor [ a b ] locals [ label-a label-b ] set label-a label-of a set label-b label-of random-one-of b ifelse label-a = label-b [ report "0" ] [ report "1" ] end ; reports true when the CRC division is finished to-report check-for-done locals [ div-bit-set working-line working-y num-working curr-x done?] set div-bit-set dividend-bit with [ label-color = yellow ] set num-yellow count div-bit-set ask min-one-of working [ ycor ] [ set working-y ycor] set working-line working with [ (ycor = working-y) and (label-color != red) ] set done? false set curr-x min-one-of working-line [ xcor ] while [ label-of curr-x = "0" and not done? ] [ ask curr-x [ set label-color red ] set working-line working-line with [ label-color != red ] ifelse count working-line > 0 [ set curr-x min-one-of working-line [ xcor ] ] [ set done? true ] ] set num-working count working-line ifelse (num-yellow + num-working) < length generator [ report true ] [ report false ] end ; do all remaining steps to go ifelse step < 16 [ one-step ] [ stop ] end ; do a single step (whichever comes next) to one-step locals [which-step] set which-step "step" + step if ( step < 16) [ run which-step ] end to show-again set number 0 set x 0 set y 0 ask turtles [ die ] ask patch-at -20 -35 [ set plabel "" ] explain 1 "" explain 2 "" set doneyet? false set step 0 set original clean-input crystal end to ask-other locals [ guess target question ] set guess user-yes-or-no? ("Did an error occur during transmission?") while [ step < 16 ] [ go ] set target final-answer ifelse guess = target [ user-message random-one-of praise ] [ user-message "I'm sorry, but the correct answer is " + target] end ; ask a quiz question to quiz locals [ save-slow ] without-interruption [ setup ] set save-slow slow-motion set slow-motion 0 wait .5 ask-other set slow-motion save-slow end ; cleans up the user input to-report clean-input [guess] locals [ pos k upper lowerList] set guess remove " " guess set guess remove "," guess report guess end ; adds a space in the number so it can be read easier to-report add-space [ space-number ] locals [ save k ] set save "" set space-number reverse clean-input space-number set k 0 while [ (length space-number) > 0 ] [ set save (word last space-number save ) set space-number butlast space-number set k (k + 1) if (k = 4) and (length space-number > 0) [ set save (word " " save ) set k 0 ] ] set space-number save report reverse space-number end ; *** NetLogo Model Copyright Notice *** ; ; Copyright 2004 by Teresa W. Carrigan. All rights reserved. ; ; Permission to use, modify or redistribute this model is hereby granted, ; provided that both of the following requirements are followed: ; a) this copyright notice is included. ; b) this model will not be redistributed for profit without permission ; from Teresa W. Carrigan. ; Contact Teresa W. Carrigan for appropriate licenses for redistribution ; for profit. ; ; To refer to this model in academic publications, please use: ; Barchet, C and Carrigan, T. (2004). Cyclic Redundancy Check Error Detection Simulation model. ; Blackburn College, Carlinville IL. ; ; In other publications, please use: ; Copyright 2004 by Crystal R. Barchet and Teresa W. Carrigan. All rights reserved. ; ; *** End of NetLogo Model Copyright Notice *** @#$#@#$#@ GRAPHICS-WINDOW 5 10 667 341 81 37 4.0 1 18 1 1 1 CC-WINDOW 168 446 448 588 Command Center BUTTON 13 346 76 379 NIL setup NIL 1 T OBSERVER T BUTTON 79 347 160 380 step one-step NIL 1 T OBSERVER T SLIDER 489 348 661 381 slow-motion slow-motion 0 1 0.0 0.1 1 NIL BUTTON 163 347 226 380 NIL go T 1 T OBSERVER T BUTTON 230 347 328 380 NIL show-again NIL 1 T OBSERVER T BUTTON 332 348 395 381 quiz quiz NIL 1 T OBSERVER T @#$#@#$#@ WHAT IS IT? ----------- This model demonstrates receiving a message using Cyclic Redundancy Check Error Detection. HOW IT WORKS ------------ A generator is chosen randomly from a list of allowed generators, and a random message is created. This message is divided by the generator by using modulo 2 arithmetic, which is the same as XOR. If the remainder is 0, then no errors occured during transmission, and then one bit less than the number of bits in the generator is stripped from the end of the transmitted message. If the remainder is not 0, then an error occured during transmission and the original message can not be recovered. HOW TO USE IT ------------- The setup button generates a random message and selects a random generator. The slow-motion slider is an easy way to adjust the speed of the demonstration. Set it to zero if you want to just see the answer quickly. 0.2 is a good setting for most purposes. The step button does whatever step comes next, and then stops so you can take notes. The go button finishes the entire problem, at a speed set by the slow-motion slider. The show-again button starts the exact problem from the beginning. You may then click either the step button or the go button to see the same demonstration. The quiz button generates a random problem and then asks you to determine the answer. Please note that you can use the show-again button after a quiz to see all the steps in getting the correct answer. THINGS TO NOTICE ---------------- When the transmitted message is all zeroes, then there was no error during transmission. When the remainder is not all zeroes, an error occurred and the original message can not be recovered. We do not pad with zeroes before division, nor do we stip bits before division. THINGS TO TRY ------------- Set the slow-motion slider to about .2 seconds (or slower) and press the step button several times. Watch the demonstration of each step. Set the slow-motion slider to about .2 seconds and press the go button. Watch the entire demonstration. Do each step by hand, then press step to check your work. EXTENDING THE MODEL ------------------- Allow the user to input the beginning message. Allow the user to input the generator. NETLOGO FEATURES ---------------- "min-one-of" reports the agent in the agentset that reports the lowest value for the given reporter. "max-one-of" reports the agent in the agentset that reports the highest value for the given reporter. "count" reports the number of agents in the given agentset. "hatch 1" tells each turtle to create one turtle identical to itself. RELATED MODELS -------------- Cyclic Redundancy Check CREDITS AND REFERENCES ---------------------- This model was written by Crystal Barchet and Teresa Carrigan, 2004. Permission to use, modify or redistribute this model is hereby granted, provided that both of the following requirements are followed: a) this copyright notice is included. b) this model will not be redistributed for profit without permission from Teresa Carrigan. Contact Teresa Carrigan for appropriate licenses for redistribution for profit. To refer to this model in academic publications, please use: Barchet, C. and Carrigan, T. (2004). Cyclic Redundancy Check Error Detection Simulation Blackburn College, Carlinville, IL. In other publications, please use: Copyright 2004 by Crystal R. Barchet and Teresa Carrigan. All rights reserved. FOR MORE INFORMATION -------------------- For more information about Cyclic Redundancy Check Error Detection, see one of the following textbooks: [1] Null, L. and Lobur, J. "Essentials of Computer Organization and Architecture", First Edition, Jones & Bartlett, pages 73-76. [2] Murdocca, M. and Heuring, V. "Principles of Computer Architecture", First Edition, Prentice Hall, page 365-366 [3] Forouzan, B. Data Communications and Networking, Third Edition, McGrawHill, pages 249-253. @#$#@#$#@ default true 0 Polygon -7566196 true true 150 5 40 250 150 205 260 250 ant true 0 Polygon -7566196 true true 136 61 129 46 144 30 119 45 124 60 114 82 97 37 132 10 93 36 111 84 127 105 172 105 189 84 208 35 171 11 202 35 204 37 186 82 177 60 180 44 159 32 170 44 165 60 Polygon -7566196 true true 150 95 135 103 139 117 125 149 137 180 135 196 150 204 166 195 161 180 174 150 158 116 164 102 Polygon -7566196 true true 149 186 128 197 114 232 134 270 149 282 166 270 185 232 171 195 149 186 149 186 Polygon -7566196 true true 225 66 230 107 159 122 161 127 234 111 236 106 Polygon -7566196 true true 78 58 99 116 139 123 137 128 95 119 Polygon -7566196 true true 48 103 90 147 129 147 130 151 86 151 Polygon -7566196 true true 65 224 92 171 134 160 135 164 95 175 Polygon -7566196 true true 235 222 210 170 163 162 161 166 208 174 Polygon -7566196 true true 249 107 211 147 168 147 168 150 213 150 arrow true 0 Polygon -7566196 true true 150 0 0 150 105 150 105 293 195 293 195 150 300 150 bee true 0 Polygon -256 true false 152 149 77 163 67 195 67 211 74 234 85 252 100 264 116 276 134 286 151 300 167 285 182 278 206 260 220 242 226 218 226 195 222 166 Polygon -16777216 true false 150 149 128 151 114 151 98 145 80 122 80 103 81 83 95 67 117 58 141 54 151 53 177 55 195 66 207 82 211 94 211 116 204 139 189 149 171 152 Polygon -7566196 true true 151 54 119 59 96 60 81 50 78 39 87 25 103 18 115 23 121 13 150 1 180 14 189 23 197 17 210 19 222 30 222 44 212 57 192 58 Polygon -16777216 true false 70 185 74 171 223 172 224 186 Polygon -16777216 true false 67 211 71 226 224 226 225 211 67 211 Polygon -16777216 true false 91 257 106 269 195 269 211 255 Line -1 false 144 100 70 87 Line -1 false 70 87 45 87 Line -1 false 45 86 26 97 Line -1 false 26 96 22 115 Line -1 false 22 115 25 130 Line -1 false 26 131 37 141 Line -1 false 37 141 55 144 Line -1 false 55 143 143 101 Line -1 false 141 100 227 138 Line -1 false 227 138 241 137 Line -1 false 241 137 249 129 Line -1 false 249 129 254 110 Line -1 false 253 108 248 97 Line -1 false 249 95 235 82 Line -1 false 235 82 144 100 bird1 false 0 Polygon -7566196 true true 2 6 2 39 270 298 297 298 299 271 187 160 279 75 276 22 100 67 31 0 bird2 false 0 Polygon -7566196 true true 2 4 33 4 298 270 298 298 272 298 155 184 117 289 61 295 61 105 0 43 boat1 false 0 Polygon -1 true false 63 162 90 207 223 207 290 162 Rectangle -6524078 true false 150 32 157 162 Polygon -16776961 true false 150 34 131 49 145 47 147 48 149 49 Polygon -7566196 true true 158 33 230 157 182 150 169 151 157 156 Polygon -7566196 true true 149 55 88 143 103 139 111 136 117 139 126 145 130 147 139 147 146 146 149 55 boat2 false 0 Polygon -1 true false 63 162 90 207 223 207 290 162 Rectangle -6524078 true false 150 32 157 162 Polygon -16776961 true false 150 34 131 49 145 47 147 48 149 49 Polygon -7566196 true true 157 54 175 79 174 96 185 102 178 112 194 124 196 131 190 139 192 146 211 151 216 154 157 154 Polygon -7566196 true true 150 74 146 91 139 99 143 114 141 123 137 126 131 129 132 139 142 136 126 142 119 147 148 147 boat3 false 0 Polygon -1 true false 63 162 90 207 223 207 290 162 Rectangle -6524078 true false 150 32 157 162 Polygon -16776961 true false 150 34 131 49 145 47 147 48 149 49 Polygon -7566196 true true 158 37 172 45 188 59 202 79 217 109 220 130 218 147 204 156 158 156 161 142 170 123 170 102 169 88 165 62 Polygon -7566196 true true 149 66 142 78 139 96 141 111 146 139 148 147 110 147 113 131 118 106 126 71 box true 0 Polygon -7566196 true true 45 255 255 255 255 45 45 45 butterfly1 true 0 Polygon -16777216 true false 151 76 138 91 138 284 150 296 162 286 162 91 Polygon -7566196 true true 164 106 184 79 205 61 236 48 259 53 279 86 287 119 289 158 278 177 256 182 164 181 Polygon -7566196 true true 136 110 119 82 110 71 85 61 59 48 36 56 17 88 6 115 2 147 15 178 134 178 Polygon -7566196 true true 46 181 28 227 50 255 77 273 112 283 135 274 135 180 Polygon -7566196 true true 165 185 254 184 272 224 255 251 236 267 191 283 164 276 Line -7566196 true 167 47 159 82 Line -7566196 true 136 47 145 81 Circle -7566196 true true 165 45 8 Circle -7566196 true true 134 45 6 Circle -7566196 true true 133 44 7 Circle -7566196 true true 133 43 8 circle false 0 Circle -7566196 true true 35 35 230 divisbar true 0 Rectangle -7566196 true true 50 35 79 288 Rectangle -7566196 true true 53 15 268 44 Rectangle -7566196 true true 51 14 54 34 Rectangle -7566196 true true 48 31 52 34 equalbar true 0 Rectangle -7566196 true true 29 240 267 269 person false 0 Circle -7566196 true true 155 20 63 Rectangle -7566196 true true 158 79 217 164 Polygon -7566196 true true 158 81 110 129 131 143 158 109 165 110 Polygon -7566196 true true 216 83 267 123 248 143 215 107 Polygon -7566196 true true 167 163 145 234 183 234 183 163 Polygon -7566196 true true 195 163 195 233 227 233 206 159 sheep false 15 Rectangle -1 true true 90 75 270 225 Circle -1 true true 15 75 150 Rectangle -16777216 true false 81 225 134 286 Rectangle -16777216 true false 180 225 238 285 Circle -16777216 true false 1 88 92 spacecraft true 0 Polygon -7566196 true true 150 0 180 135 255 255 225 240 150 180 75 240 45 255 120 135 thin-arrow true 0 Polygon -7566196 true true 150 0 0 150 120 150 120 293 180 293 180 150 300 150 top true 0 Rectangle -7566196 true true 45 16 260 44 truck-down false 0 Polygon -7566196 true true 225 30 225 270 120 270 105 210 60 180 45 30 105 60 105 30 Polygon -8716033 true false 195 75 195 120 240 120 240 75 Polygon -8716033 true false 195 225 195 180 240 180 240 225 truck-left false 0 Polygon -7566196 true true 120 135 225 135 225 210 75 210 75 165 105 165 Polygon -8716033 true false 90 210 105 225 120 210 Polygon -8716033 true false 180 210 195 225 210 210 truck-right false 0 Polygon -7566196 true true 180 135 75 135 75 210 225 210 225 165 195 165 Polygon -8716033 true false 210 210 195 225 180 210 Polygon -8716033 true false 120 210 105 225 90 210 turtle true 0 Polygon -7566196 true true 138 75 162 75 165 105 225 105 225 142 195 135 195 187 225 195 225 225 195 217 195 202 105 202 105 217 75 225 75 195 105 187 105 135 75 142 75 105 135 105 wolf false 0 Rectangle -7566196 true true 15 105 105 165 Rectangle -7566196 true true 45 90 105 105 Polygon -7566196 true true 60 90 83 44 104 90 Polygon -16777216 true false 67 90 82 59 97 89 Rectangle -1 true false 48 93 59 105 Rectangle -16777216 true false 51 96 55 101 Rectangle -16777216 true false 0 121 15 135 Rectangle -16777216 true false 15 136 60 151 Polygon -1 true false 15 136 23 149 31 136 Polygon -1 true false 30 151 37 136 43 151 Rectangle -7566196 true true 105 120 263 195 Rectangle -7566196 true true 108 195 259 201 Rectangle -7566196 true true 114 201 252 210 Rectangle -7566196 true true 120 210 243 214 Rectangle -7566196 true true 115 114 255 120 Rectangle -7566196 true true 128 108 248 114 Rectangle -7566196 true true 150 105 225 108 Rectangle -7566196 true true 132 214 155 270 Rectangle -7566196 true true 110 260 132 270 Rectangle -7566196 true true 210 214 232 270 Rectangle -7566196 true true 189 260 210 270 Line -7566196 true 263 127 281 155 Line -7566196 true 281 155 281 192 wolf-left false 3 Polygon -6524078 true true 117 97 91 74 66 74 60 85 36 85 38 92 44 97 62 97 81 117 84 134 92 147 109 152 136 144 174 144 174 103 143 103 134 97 Polygon -6524078 true true 87 80 79 55 76 79 Polygon -6524078 true true 81 75 70 58 73 82 Polygon -6524078 true true 99 131 76 152 76 163 96 182 104 182 109 173 102 167 99 173 87 159 104 140 Polygon -6524078 true true 107 138 107 186 98 190 99 196 112 196 115 190 Polygon -6524078 true true 116 140 114 189 105 137 Rectangle -6524078 true true 109 150 114 192 Rectangle -6524078 true true 111 143 116 191 Polygon -6524078 true true 168 106 184 98 205 98 218 115 218 137 186 164 196 176 195 194 178 195 178 183 188 183 169 164 173 144 Polygon -6524078 true true 207 140 200 163 206 175 207 192 193 189 192 177 198 176 185 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