# Main Command: Go
# Twisted Rose Animation 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 PtoR :RadDist :Theta
  # convert polar to rectangular co-ordinates
  LocalMake "X :RadDist *Sin :Theta
  LocalMake "Y :RadDist *Cos :Theta
  Output List :X :Y
End

to angcol :theta
  Make "Red Absolute 255*Cos :Theta
  Output ( List :Red 0 255 )
end

to spiral :angle :twist
  # Twisted Rose Curves
  Make "Radius 180*Sin(4*:Angle) 
  Make "Angle :Angle + 20*Sin :Twist*:Angle
  SetPW Width :Angle :Radius     #comment out for plain pen 
  SetPC AngCol 30 + 3*:Angle 
  SetPos P2R :Radius :Angle PenDown Wait 2
end

to width :angle :radius
  SetH Towards PtoR :Radius :Angle
  Output 2*(1.5+Sin (45 + 2*Heading))
end

to go
  New
  For [Twist 0 24] [ 
    For [Angle 0 360] [
      Spiral :Angle :Twist] Wait 100 Wash]
end