# Constructions with Paper Folding

Constructions with Paper Folding

You can fold the unit square piece of paper, yellow on one side, light blue on the other, by dragging its lower-left corner. Use the 2D sliders to place the points , , … on the paper. There are three special cases:

A

B

• Messner's method for doubling a cube using origami

• Abe's angle trisection

• Constructing a point on a parabola given by a horizontal directrix and focus . Suppose the point is on the directrix; find a crease that maps into . Then the intersection of the crease with the vertical line through is on the parabola.

A

B

B

A

B