Infinity boxes, like those old ones you could buy at places like Spencer Gifts and Newbury comics were basically 2 mirrors facing each other with some sort of light in between, however one of the mirrors was one-way glass, allowing you to see through it and see the back mirror without getting your own reflection in the mix. This effect is used a lot for bottomless pits or wells. here are a couple tutorials on similar projects that will give you the basics you need to know to do what you want, if I understand you right. https://www.youtube.com/watch?v=CMxBAn_LdX0 and https://www.youtube.com/watch?v=sAPGw0SD1DE
Infinity Illusion
