Discussion, spinning disc as mask concept

I think a zoetrope would be able to project a series of (more-or-less) static 2D images using two counterrotating discs. Essentially, what you see is a line scanning over the image (e.g. vertically), which is the slit (on one of the discs). As that slit passes over the image, the other disc is moving in the opposite direction with the 2D image on it (upside-down). If you think about it line-by-line, you end up (accounting for persistence of vision/finite exposure time) with a line-scanned version of the image, the right way up. However, you lose light by a factor of 1/(number of lines in your image) which is a lot!

I think there may be versions of a zoetrope that use a lens for better efficiency, but my knowledge runs out there…