basket/examples/sierpinski.scm

(add-to-load-path (dirname (dirname (current-filename))))
(use-modules (basket))

(define (sierpinski x y z n)
  (if (= n 0)
    `((,x ,y ,z))
    (append
      (sierpinski x (vec-midpoint x y) (vec-midpoint x z) (1- n))
      (sierpinski y (vec-midpoint y x) (vec-midpoint y z) (1- n))
      (sierpinski z (vec-midpoint z x) (vec-midpoint z y) (1- n)))))

(define image
  `(fill
     ,(sierpinski '(0.5 . 0) '(0 . 1) '(1 . 1) 8)))

(render-cairo-png image 1024 (cadr (program-arguments)))