Labirynt cz II

Normalnie bym nie pisał - bo sesja, ale udało mi się odratować kod źródłowy słynnego już labiryntu. Oto i on:

Rysuj
  | form pen ile i |
  form := Display.
  pen := Pen newOnForm: form.
  pen up.
  form fillWhite.
 
  ile := lab size.
  i := 1.
  [i <= ile] whileTrue:
  [
    pen goto: (lab at: i).
    pen down.
    pen goto: (lab at: (i+1)).
    pen up.
    i := i + 2.
  ]

  pen goto: 0@0.
  pen down.
  pen goto: (10*xsize)@0.
  pen goto: (10*xsize)@(10*(ysize // 2)).
  pen goto: 0@(10*(ysize // 2)).
  pen goto: 0@0.
  pen up.

  pen goto: 0@(10*((ysize // 2) +1)).
  pen down.
  pen goto: (10*xsize)@(10*((ysize // 2) +1)).
  pen goto: (10*xsize)@(10*ysize).
  pen goto: 0@(10*ysize).
  pen goto: 0@(10*((ysize // 2) +1)).
  pen up.

  pen goto: 0@(10*((ysize // 2) +1) + 1).
  pen down.
  pen goto: (10*xsize)@(10*((ysize // 2) +1) + 1).
  pen up.

  pen goto: 0@(10*((ysize // 2)) - 1).
  pen down.
  pen goto: (10*xsize)@(10*((ysize // 2)) - 1).
  pen up.

  [Sensor keyboardPressed] whileFalse: [].
  Display restore.

Stworz: x y: y
  | r v |
  xsize := x.
  ysize := y.
  r := Random new.
  lab := OrderedCollection new.
  0 to: (x-1) do:
    [:x1 |
      0 to: (y-1) do:
        [:y1 |
          (y1 = (y // 2)) ifFalse:
          [
            v := r nextInt: 5.
            (v > 2) ifTrue:
            [ lab addLast: (10*x1)@(10*y1)
              lab addLast: (10*(x1+1))@(10*y1) ].
            (v < 4) ifTrue:
            [ lab addLast: (10*x1)@(10*y1)
              lab addLast: (10*x1)@(10*(y1+1)) ].
          ].
        ].
    ].