Which are prisms among the following?
Unsharpened pencil
A box
A table calendar
A prism is a solid geometric figure whose two ends are congruent and parallel rectilinear figures and whose sides are parallelograms.
Usually unsharpened pencil has two hexagonal ends and six lateral faces. A box has two rectangular ends and four lateral faces. A table calendar has two triangular ends and three lateral faces. So, these three are examples of the prism.