# Main Command: Go
# Cycloid Curves 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 curve :angle
  If :Angle > :MaxAngle [Stop]
  Right 1 Forward Sine :N*:Angle
  Curve :Angle+1
end

to display :n
  # write header info
  SetPC White PenUp SetH 0
  SetPos [-190 180]
  If (:N > 1) [Label List "Hypo_Cycloid :N] [Label List "Epi_Cycloid :N] 
end

to go
  New PenDown 
  Make "Curves [
  [5 180] [4 360] [3 180] [2 360] [1.5 720] [1.333 1080]
  [0.666 1080] [0.5 720] [0.333 540] [0.25 1440] [0.2 900] [0.02 4500] ]
  Repeat Count :Curves [ 
    Make "N Item 1 Item RepCount :Curves
    Make "MaxAngle Item 2 Item RepCount :Curves
    Wash Display :N SetPC Green Home PenDown Curve 0 Wait 60]
end