Hyperboloid Made of Coaster and Elastic Cord

Hyperboloids are beautiful curved surfaces. It is a curved surface, but it consists only of straight lines. This instruction uses a coaster and a rubber cord to make this hyperboloid.

• Coaster x2
• Elastic cord (3m)
• Wood stick (10cm)
• Wood screw x2

Draw a circle on the paper that is the same size as the coaster.

Divide the circumference into 24 parts and draw a point at the position to make a hole.

Drill a hole at the drawn point. (same diameter with elastic cord)

Stack two coasters and make holes at once.

Make a hole in the center.

Hole size is little bigger of the wood screw for free rotation.

Make a hole in the center of the stick both side.

Hole size is according to wood screw.

Assembly the coaster and stick with screw.

One side should be tight.

Leave a space on the other side for free rotation.

Thread the string between the two coasters in order.

Let's twist!

The shape you find is hyperboloid of revolution.