gistfile1.scm

    (
      (def closed (c)
        (or
          (<= (- (cube-max-x c) (cube-min-x c)) 1)
          (<= (- (cube-max-z c) (cube-min-z c)) 1)
        )
      )
      (defrec pyramid (c m)
        (begin
          (cube-set-walls c m)
          (if (closed c)
            unit
            (pyramid (cube-shift-y (cube-shrink-in c 1) 1) m)
          )
        )
      )
      (def house (start-point h w d floor-m walls-m roof-m)
        (let (c (cube-grow-up (cube-expand-z (cube-expand-x (cube start-point start-point) w) d) h))
          (begin
            (cube-set-all   c (material "air"))
            (cube-set-floor c floor-m)
            (cube-set-walls c walls-m)
            (pyramid (cube-expand-out (cube-ceiling c) 1) roof-m)
          )
        )
      )
      (house XYZ 8 8 20 (material "stone") (material "brick") (material "wood"))
    )