The lens I bought was awful. Its focal point was too close to the surface, so I couldn't use multiples along side, and large lenses were prohibitively expensive. This has to be repeatable, and rear projection tv's never really took off in the uk, and i suspect not in the target countries either. So plan B......

(PS, I'm not 5, that just my handwriting)

So the idea is to use conventional foil to make a parabolic mirror in the style of a reflector telescope. The cost benefit should outweigh the loss of light and this could be made from a light wood frame , some papier-mache and a conventional mirror (and math of course)