- doesn't roll well, but folds nicely when scored (will discuss this later). Structures made from this keep their shape better than those made from the cereal-box variety. which comes in different thicknesses. Check out the size of the flutes - the smallest flute (somewhere in the middle of the stack) is in a USPS priority mail box. Double Wall Corrugated Cardboard - double layer of flutes: See - compared to the single wall cardboard below it. There does exist Triple Wall Corrugated Cardboard, but I haven't seen it yet (drats) . Updated in Oct 2011: Yes, I have! Hurrah! Here it is: Now this is one of my particularly precious stash treasures: it is extra thick, extra strong, surprisingly light and has the prettiest pattern of corrugation. Quite different from the regular corrugated cardboard. Almost honey-comb like. I wish I knew what it was called. We found two of these strips in a box containing some household appliance, and used the first one for a ramp for matchbox cars. It lasted years. Slightly less rare, but equally valued is White Cardboard . It's like the cashmere of cardboard. White on one side means the kids can have a field day coloring it in really bright colors. Whenever I find white cardboard, I save it for special occasions. Then there are the other kinds of 'cardboard' like paper board, cardstock, poster board but you know those already. What Tools Do I Need? To each his/her own. I'll share what I