Logo Arts

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

To Init
  # create empty list
  Make "Y [ ]
  Repeat 257 [ Make "Y LPut 0 :Y ]
End

To Display
  # write header title
  SetPC White PenUp
  SetPos [-190 180] Label [Blancmange Curve]
End

To Blancmange
  # calculate heights
  Make "Index 256
  For [N 1 8] [
    For (List "M 1 256 :Index) [
      Make "Average ((Item :M :Y) + Item (:M + :Index ) :Y) / 2
      Make "Y SetItem :Y (:M+:Index/2) (:Index + :Average) ]
    Make "Index :Index / 2 ]
End

To Draw
  # draw curves from list
  Make "Index 256
  For [N 1 8] [
    Wash Display
    PenUp SetPos [-127 -100] PenDown SetPC Pink
    For (List "P 1 257 :Index) [SetPos List :P-128 (Item :P :Y) / 2 -100]
    Make "Index :Index / 2 Wait 80]
End

To Go
  New Init
  Blancmange Draw
End