Osmosis Model

breed [water waters]

to setup
  clear-all
  reset-ticks
  ask patches with [pycor = 0] [set pcolor yellow]
  set-default-shape water "circle"
  create-water (num-water) [
   setxy 0 8 fd random 5
    set color blue
  ]
end 

to go
  move-waters
  ask turtles [
    repel-too-close-neighbor
    repel-too-close-patch
  ]
 tick
end 

to move-waters
  ask water [forward 1]
  wait 0.1
end 

to repel-too-close-neighbor
  let too-near one-of other turtles in-radius .05
  if too-near != nobody [
    face too-near
    rt 180
  ]
end 

to repel-too-close-patch
 let too-near one-of other patches in-radius 1
  if too-near != nobody [
    face too-near
  ]
end