aUCBLogo Demos and Tests / sierp

to sierp
   ; This program creates three equivalent forms using various looping structures
   cs ht
   pu setxy -250 -100 seth 11  pd
   make "t timemilli
   image_left
   pr timemilli-:t
   pu setxy 120 -100 seth 11  pd  setpc 0
   make "t timemilli
   image_right 0
   pr timemilli-:t
   pu home st
end

to image_left
   ; nested repeat
   repeat 3 ~
   [   setpc 9 fd 128
      repeat 3 ~
      [   setpc 10 fd 64
         repeat 3 ~
         [   setpc 11 fd 32
            repeat 3 ~
            [   setpc 12 fd 16
               repeat 3 ~
               [   setpc 13 fd 8
                  repeat 3 ~
                  [   setpc 14 fd 4
                     repeat 3 ~
                     [   setpc 15 fd 2
                        repeat 3 ~
                        [   setpc 16 fd 1
                           rt 120
                        ]
                        rt 120
                     ]
                     rt 120
                  ]
                  rt 120
               ]
               rt 120
            ]
            rt 120
         ]
         rt 120
      ]
      rt 120
   ]
end

to triangle
   lt :tilt
   repeat 3 ~
   [   setpc 17-:level
      fd :size
      fractal :size/2 :level-1
      rt 120
   ]
   rt :tilt
end

to fractal :size :level
   if :level < 1 [stop]
   triangle
end

to image_right :tilt
   ; recursive
   rt :tilt
   fractal 128 8
end