moss

turtles-own [ life ]

to setup
  ca
  crt population [
    set color one-of [ red blue ]
    setxy random-xcor random-ycor
  ]
  ask patch 12 12 [
    set pcolor blue
  ]
  ask patch -12 -12 [
    set pcolor red
  ]
  reset-ticks
end 

to go
  ask turtles with [ pcolor = black ] [
    let my-color color
    ifelse any? neighbors4 with [ pcolor = my-color ] [
      set pcolor my-color
      die
    ] [
      set life life + 1
      rt random 30
      lt random 30
      fd 0.5
    ]
  ]
  tick
end