Here is the evolution of the triship model from basic concept to final creation.

Basic idea was to use a bunch of these hinge-like pieces.

Four of them together, create a box.

From this, I added some "fins"...

... and created a rocket like model. The cone is not actually attached.

However, I was not sure how to attached the "nose" so I turned the box inside-out and was able to create the model.

I thought that the cone looked odd, so I changed one to a cockpit to make a space ship.

Thinking that it was too short, I expanded the base.

Here is a basic idea of the ship at first.

Played around with some variations of the ship structure, added some wings, and we get the final "triship" model.