One of those collapsible beds?

Well, the bed collapsed. It's a collapsible bed.

The crew are trying to clear two of the collapsible boats.

Leave it! There's no time! We'll try and free the starboard collapsible!

It's when part of the intestine folds into another part, sort of like a collapsible telescope.

Back on Earth, shape memory alloys are used to open up clogged arteries as stents, which are small collapsible springs that force open passages.

That's symmetric, and it collapses down into these three triangles, which collapse down into one triangle, and collapsible hexagons are, you suppose, cool enough to at least amuse you a little bit during your class.