Maekawa's theorem

Maekawa's theorem is a theorem in the mathematics of paper folding named after Jun Maekawa. It relates to flat-foldable origami crease patterns and states that at every vertex, the numbers of valley and mountain folds always differ by two in either direction. The same result was also discovered by Jacques Justin and, even earlier, by S. Murata.

Maekawa's theorem

Maekawa's theorem is a theorem in the mathematics of paper folding named after Jun Maekawa. It relates to flat-foldable origami crease patterns and states that at every vertex, the numbers of valley and mountain folds always differ by two in either direction. The same result was also discovered by Jacques Justin and, even earlier, by S. Murata.