Simple Shibboleth

turtles-own [fitness mimicry]

breed [bluebeards bluebeard]
breed [greenbeards greenbeard]
breed [guardians guardian]

to setup
  clear-all
  setup-patches
  setup-turtles
  reset-ticks
end 

to setup-patches
  ask patches with [
    pycor >= -16 and
    pycor <= -1 and
    pxcor >= -16 and
    pxcor <= 16  ]
    [ set pcolor 44 ]
  ask patches with [
    pycor <= 16 and
    pycor >= 2 and
    pxcor >= -16 and
    pxcor <= 16 ]
    [ set pcolor 33 ]
  ask patches with [
    pycor >= 0 and
    pycor <= 1 ]
  [ set pcolor blue ]
  ask patches at-points [[0 0] [0 1] [-1 0] [-1 1] [1 0] [1 1]]
  [set pcolor brown ]
end 

to setup-turtles
  set-default-shape turtles "person"
  create-bluebeards 50 [
    move-to one-of patches with [ pcolor = 44 ]
  set color 104
  set mimicry random (mimicry-modifier) + 1
  set fitness (random (100 - mimicry-modifier)) + mimicry
  ]
  create-greenbeards 50 [
    move-to one-of patches with [ pcolor = 33 ]
  set color green
  set fitness random 100 + 1
  ]
  create-guardians 1 [
    move-to patch 0 0
    set color red
  ]
end 

to go
  if count bluebeards-on patches with [ pcolor = 44 ] = 0 and
  count bluebeards-on patches with [ pcolor = brown ] = 0 and
  count bluebeards-on patches with [ pcolor = blue ] = 0
  [ stop ]
 move-bluebeards
 move-greenbeards
 detect-mimics
tick
end 

to move-bluebeards
  ask bluebeards [
    seek-safety
    avoid-water
    check-death
    blend-in
    forward 1
    ifelse show-fitness?
    [ set label fitness ]
    [ set label round ((mimicry / mimicry-modifier) * 100) ]
  ]
end 

to move-greenbeards
  ask greenbeards [
  facexy random-xcor random-ycor
  forward 1
  facexy random-xcor 16
  forward 1.1
    ]
end 

to avoid-water
  if [pcolor] of patch-here = blue or [pcolor] of patch-here = 44 [
  let target-patch patch-right-and-ahead 0 1
  if target-patch != nobody and [pcolor] of target-patch = blue [
    move-to patch 0 -7
  ]
]
end 

to seek-safety
  if [pcolor] of patch-here = 44 [
    let safety-patch patch 10 10
    if safety-patch != nobody and [pcolor] of safety-patch = 33 [
      facexy random-pxcor 16
    ]
    ]
end 

to check-death
  if fitness <= 0 [ die ]
end 

to blend-in
  if [pcolor] of patch-here = 33 [
facexy random-xcor random-ycor
  forward 1
  facexy random-xcor 12
  forward 1.1
    ]
end 

to detect-mimics
  ask guardians [
     if count turtles-at 1 0 != nobody [
      ask bluebeards-at 1 0 [
      if ((mimicry / mimicry-modifier) * 100) < detection-risk [
        set fitness fitness - cost ]
      if ((mimicry / mimicry-modifier) * 100) = detection-risk [
       if random 2 = 0 [
            set fitness fitness - cost ]
        ]
  ]
    ]
     if count turtles-at 0 0 != nobody [
      ask bluebeards-at 0 0  [
      if ((mimicry / mimicry-modifier) * 100) < detection-risk [
        set fitness fitness - cost ]
      if ((mimicry / mimicry-modifier) * 100) = detection-risk [
       if random 2 = 0 [
            set fitness fitness - cost ]
        ]
  ]
    ]
     if count turtles-at -1 0 != nobody [
      ask bluebeards-at -1 0  [
      if ((mimicry / mimicry-modifier) * 100) < detection-risk [
        set fitness fitness - cost ]
      if ((mimicry / mimicry-modifier) * 100) = detection-risk [
       if random 2 = 0 [
            set fitness fitness - cost ]
        ]
  ]
    ]
  ]
end