RPS

to setup
  ca
  ask patches [
    set pcolor one-of [ red yellow blue ]
  ]
  reset-ticks
end 

to go
  ask patches [
    if pcolor = red [ spread yellow ]
    if pcolor = yellow [ spread blue ]
    if pcolor = blue [ spread red ]
  ]
  tick
end 

to spread [ prey ]
  ask patch-set one-of patches in-radius spread-distance with [ pcolor = prey ] [
    set pcolor [ pcolor ] of myself
  ]
end 

to-report mixedness
  report mean [ count neighbors with [ pcolor != [ pcolor ] of myself ] ] of patches
end