A simple tensegrity sculpture, and although I've been interested in these for a while this was specifically inspired by this "LEGO Tensegrity Sculpture Tutorial"

Supplies

A Toilet Tube
Some thread, (Ideally, nylon "invisible" thread, but normal cotton is fine)
A pen(cil)
A Ruler
A Pair of scissors
A needle
And something like a thimble or your desk to help push needle through card

Step 1: Mark Up Your Tube and Cut It

Mark the opposite points at one end of your tube (I did this by eye but measuring would be good) and mark lines perpendicular down to the other end of the tube.

From one end of the centre line mark a point 2cm either side of the centre, and then another point 2cm up from each of these.

Then cut from the rear centre point to this 2cm by 2cm point.

Repeat for other side producing the standing Spike.

Use this as a template to cut the second one.

You should end up with two standing spikes

Step 2: Bend and Thread

This bit is trial and error be prepared for much tautening and sliding and frustration.

Mark and score a line about 2 cm from the top of the inside of the spike.

Fold these down to a 90º angle.

Pierce the spike from outside and thread through to the same point on the other spike, joining them. leave a couple of centimetres between the spikes and tie off the thread.

Now thread from the base of one spike, up to the fold on the opposite spike across spike and back down to the other side of the base (a-2-3-4, a-b-c-d on the picture) - I have tried both piercing the tube for this (the clear thread verson) and using cut slots (the black thread version) the BT version es easier to tweak, and the other is more robust.

Now you can pull and adjust the threads to bring the required even tension. All I can say to help with this is try and keep everything level and balanced and it will just happen.