# Main Command: Go
# SpiroCircle by Guy Walker
# www.logoarts.co.uk

to new
  # set default screen, pen and turtle
  ResetAll SetScreenSize [400 400] HideTurtle
  SetSC Black SetPC Green SetPS 1 PenUp
end

to spir
  For [R 0 180 4] [
    Make "S (180-:R) Make "Theta 0 
    PenUp SetPos XYCurve :R :Theta PenDown
    For [Theta 2 360 2] [SetPos XYCurve :R :Theta]
    Refresh Wash]      # put a wait in here if too fast
end

to init
  Make "A (1 + Random 7)
  Make "B (1 + Random 5)
  Make "W Minus :W
end

to xycurve :r :theta
  Make "RotA :A*:Theta
  Make "RotB :B*:Theta
  Make "X :R*(Sin :RotA) + :S*(Cos :RotB)*:W
  Make "Y :R*(Cos :RotA) + :S*(Sin :RotB)
  Output (List :X :Y)
end

to go
  New Animation Make "W 1
  Forever [Init SetPC :A Spir]
end