to chase2
  everyone [cg]
  t1, pu left 90 forward 200
  t2, pu forward 200
  t3, pu right 90 forward 200
  t4, pu back 200
  everyone [pd]
  forever [
    t1, towards "t2 forward 1
    t2, towards "t3 forward 1
    t3, towards "t4 forward 1
    t4, towards "t1 forward 1
  ]
end