How many icosominoes are there?
An icosomino is a polyomino made up of 20 squares connected edge-to-edge. The exact number of distinct icosominoes is not definitively known, but it is estimated to be around 3,000,000. The count varies based on the specific criteria used for considering two icosominoes as distinct, such as rotation and reflection. Research in combinatorial geometry continues to explore these figures.