What are pentiminos?

Pentominoes are geometric shapes formed by joining five equal-sized squares edge to edge. There are 12 unique pentomino shapes, each named after letters of the alphabet that they resemble, such as "F," "L," and "T." They are often used in puzzles and games, as well as in mathematical and recreational geometry studies. Pentominoes can be arranged in various ways to fill a rectangular area without gaps or overlaps.