The main part of the Foldscope is one long sheet of paper. Half of this is blue (that's the front portion) and the other half is yellow (which you fold to become the back of the foldscope).

A Japanese man who gives talks on the experiences of atomic bomb survivors has shown people in Norway how to fold paper ...

For amusement he began to fold the trimmed-off strips of paper in various ways, and one of the figures he made turned out to be particularly intriguing. He had folded the strip diagonally at three ...