a pencil
stuff
Real life is a real life example!
There are few "real life" examples. Tin boxes, for Quality Street, for example, or eight-sided glasses are two.
tent
An Amicelli box! THIS IS NOT TRUE IT IS HEXAGONAL!!
a pencil
A solid brick is a rectangular prism. (this one example of many)
stuff
A tent
Perhaps a beehive has a number of it.
honeycomb
Honeycomb
A gaming die.
A real life example is a Toblerone chocolate bar which is in the shape of a triangular prism.
The Pentagon Department of defense office building
Pup tent or lean-to