KJ,

My favourite triangular prism is a Toblerone chocolate bar.

The children next door have a swing set in the shape of a triangular prism.

A sheet of plywood or cardboard leaning against a wall forms a triangular prism.

With a triangular pyramid, sometimes called a tetrahedron, I came up blank. I think there might be some triangular pyramids in the trusses in my attic but I can't get up there. If you find a triangular pyramid in your house or in the school let me know.

Penny

Triangular pyramids (tetrahedra):

(1) 4-sided gaming die
(2) A corner cut off a block of butter or cheese
(3) Tetrapak of milk, juice, etc (more common in Europe)
(4) Camera tripod
(5) Volume enclosed by a spiderweb on a ceiling
(6) "Painter's pyramids" (used to support freshly painted objects, see eg the Lee Valley catalog
(7) There used to be a "Rubik's tetrahedron" on the market.

-RD