A pentomino is a five-square puzzle piece. If you took five squares,
and laid them against each other, edge to edge, you might get a shape
like this:

Rearranging some more, you might discover several other shapes. There
are exactly **twelve** different ways you can arrange five
squares, not counting for symmetrical copies. These twelve pieces have
been given names that correspond roughly to their shapes:

There are **F I L N P T U V W X Y **and** Z**
letter pieces.

You may want to make a full set of pentominoes yourself, using some
graph paper or Lego bricks. There are some nice oak, plastic or metal
pentomino sets on the market, as well.