Walking the dogs the other day, I noticed a newish Zenith 51" projection TV being scrapped behind the local repair shop. As I walked I noticed that the screen appeared to have a fresnel lens incorporated. After our walk, I went back and 5 mins. later, had an interesting 45"x25" sandwich of rigid acrylic sheet, a lenticular array and an extremely large, extremely fine pitch fresnel. A few minutes of peeling the tape away and the three readily separated. It appears to have a f.l. of about 24" or so, and readily burns grass and anything else in the way. (solar furnace anybody???) As soon as I'm done redesigning my 20x24, I'll be trying it out. So, make friends with you local TV repairman, he actually may have some interesting toys to play with. (not to mention using the rear projection lenses as incredibly fast, as in ~F1.0 or so, imaging lenses, once you remove the secondary corner correction element on the front).