So I'd like to build a clear tube about 12" in diameter and about 4 feet tall. I've got the material in my head that is like the cover material on cheap posters or frames (a flat sheet that I can roll and tape together). But for the life of me I can't think of this materials proper name. Acrylic is the only word that comes to mind, but that leads me to tubes and pipes and hard sheets which aren't what I'm looking for. Anyone have an idea? The thickness and feel from my memory is like the old transparency sheets from days-gone-by (but a little heavier).