Subroutine pythagoras_tree(x1, y1, x2, y2, depth)
    If depth > 10 Then Return

    dx = x2 - x1 : dy = y1 - y2
    x3 = x2 - dy : y3 = y2 - dx
    x4 = x1 - dy : y4 = y1 - dx
    x5 = x4 + (dx - dy) / 2
    y5 = y4 - (dx + dy) / 2
    #draw the box
    Line x1, y1, x2, y2 : Line x2, y2, x3, y3
    Line x3, y3, x4, y4 : Line x4, y4, x1, y1

    Call pythagoras_tree(x4, y4, x5, y5, depth +1)
    Call pythagoras_tree(x5, y5, x3, y3, depth +1)
End Subroutine

w = 800 : h = w * 11 \ 16
w2 = w \ 2 : diff = w \ 12

Clg
FastGraphics
Graphsize w, h
Color green
Call pythagoras_tree(w2 - diff, h - 10, w2 + diff, h - 10, 0)
Refresh
ImgSave "pythagoras_tree.jpg", "jpg"
End