Boxboard
Cereal boxes are often made from recycled paper. Because it is thick and strong, and you can use it to make a box, I call it boxboard.
My students kept a recycle bag at home. When they finished with a cereal box, they carefully broke it down, folded it flat, and placed it in the bag. When the bag was full, they brought it to our class.
In class they placed the boxboard in several of the laundry baskets we had in the room. This made it easy to carry the material to  wherever we were working.
Boxboard  and graph paper can be used to make a design.
Making a Box