I wonder how much of this is due to a significant understanding of the underlying principles, that simply weren't present at the time? Today, especially in this community, we have an almost intuitive understanding of layers and parallax etc. My first thought on seeing the title was "uhh, mechanical parallax, neat!" and I was actually a bit disappointed that the machine could be "programmed" to move the planes automatically. This device can not have felt obvious to many people, at all, in 1957.