One Cut CO2 puzzle

Cutting CO2 is a challenge we all must face. Solve the puzzle - one cut will suffice!

“Fold-and-cut theorem”

Folding and making one straight cut suffice. For any shape with straight edges there is a way to fold a piece of paper so that this shape can be cut out with a single straight cut.

Proved in 1998 by Anna Lubiw, Martin and Erik Demaine; first examples by Kan Chu Sen in Wakoku Chiyekurabe in 1721, Japan.


Download and print the one cut CO2 worksheet

Fold only along the thick solid and dashed lines until the shape collapses flat. Thick solid lines are ‘mountain’ folds, dashed lines are ‘valley’ folds. Once folded, make one straight cut along the thin line. Unfold.

Download the One cut Co2 worksheet (pdf)