Many antique black powder rifle barrels were made in an octagonal shape.
A trampoline
stuff
i dont tell you so ....
There are few "real life" examples. Tin boxes, for Quality Street, for example, or eight-sided glasses are two.
Function is a practical purpose an item serves in life. An item for aesthetics only is just for looks.
A solid brick is a rectangular prism. (this one example of many)
A pencil.
A tent
Looks at Life was created in 1967.
A gaming die.
A real life example is a Toblerone chocolate bar which is in the shape of a triangular prism.
Binoculars, cameras, telescopes,
a doghouse