Anybody know the name of this children's book from the 70's?

Question

When I was in primary school back in the late 70's/early 80's my favourite picturebook in the school library was a very psychedelic story about a boy who found a box and climbed inside and found another box. As the story progressed the boxes inside kept getting bigger and he met some strage chracters inside. Any ideas?

Answer 1

Are you sure it wasn't from the comic strip "Calvin & Hobbes," when they turned a cardboard box into the "Transmogrifier"?