Building a Tetrahedron!

These pyramid shaped constructions are a great way to learn tripod and square lashings and have fun doing it.

Equipment List

Build the tetrahedron

You can assemble the tetrahedron several ways. It really does not matter. Eventually the structure should look like the following diagram.

My favourite method though, is to start with the spars laid out on the floor as shown in the next diagram.

Tie all the lashings, and then lift the centre (at the tripod lashing) and swing #1 to #2, #3 to #4, and #5 to #6. It may seem complicated the first time you do it but it is a very quick way to assemble the tetrahedron!

Secure the spars at the corners with 3 more square lashings.

Build the thrower!

The final touch is to add the thrower that will launch the tennis balls. It will look more or less like this!

The thrower itself is made from a shallow tin can like a tuna fish tin. I attach the 1m (3ft) bungee cords to it with filament tape (used for packing). Remove the hooks from the bungee cords at the tin can end to prevent catching people's hands! The hooks can be left on the other ends to help you attach it to the corners of the tetrahedron.

Playing the game

You can invent many ways to use these toys but our favourite when we are indoors is to create large pyramids of empty tin cans and see who can cause them to collapse first.