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

To New
  # set default screen, pen and turtle values
  ResetAll SetScreenSize [400 400] HideTurtle
  SetSC Black SetPC Green SetPS 1 PenUp
End

To Yin :Size [:Parity 1]
  # yin shape drawn from centre (tp)
  # default parity of 1, use minus 1 for mirror image
  rArc 180 :Size/2 Back :Parity *:Size/4
  rArc 180 :Size/4 Back :Parity *:Size/2
  rArc 180 :Size/4 Back :Parity *:Size/4 Left 180
End

To YinYang :Size
  If :Size < 12 [Stop]
  Right 15 Repeat 2 [
    SetPC [0 192 192]
    Yin :Size Forward :Size/4
    If :Col = True [SetPC Aqua] [SetPC Leaf]
    Make "Col Not :Col
    Fill Wait :Size/6
    YinYang :Size/2
    Back :Size/4 Left 180] Left 15
End

To rArc :Angle :Radius
  # clockwise arc drawn relative to turtle heading
  Arc :Radius Heading :Angle+Heading Right :Angle
End

To Aqua
  Output [0 128 255]     # return aqua rgb color
End

To Leaf
  Output [0 255 128]     # return leaf rgb color
End

To Go
  New Make "Col True
  YinYang 384
End