((eq? head 'color) (interpret (caddr expr)))
((eq? head 'rotate-stencil) (interpret (caddr expr)))
((eq? head 'translate-stencil) (interpret (caddr expr)))
+ ;; for signatures, we indeed want the _outline_ rather than
+ ;; the expression interpreted. Right?
+ ((eq? head 'with-outline) (interpret (cadr expr)))
((eq? head 'combine-stencil)
(for-each interpret (cdr expr)))
(else