# Main Command: Go
# Golden Spiral 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 section :side
  If :Side < 2 [Stop]     # stop when side too short
  SetPC Green Square :Side     # comment out for curve only
  SetPC Red Curve :Side     # comment out for squares only
  Section :Side*0.618     # do again with smaller side
end

to square :side
  Repeat 4 [Forward :Side Right 90]
end

to curve :side
  Make "Step :Side*0.0524     # heading correction pi/60
  Right 1.5
  Repeat 30 [Forward :Step Right 3 Wait 4]     # 90 degree arc in 30 steps
  Left 1.5
end

to lines
  SetPC [0 0 128]     # draw crossed lines in blue
  PenUp SetPos [-185 88]
  PenDown SetPos [184 -140]
  PenUp SetPos [184 88]
  PenDown SetPos [43 -140] Wait 30
end

to go
  New Lines SetPos [-185 -140]
  Section 228     # begin with square of side 228
end