Pictures on grids

• The basic components that make up pictures on grids are cells, sites and bonds.

• There are 3 basic families of connected pictures on grids:
• polyominoes made up of cells,
• site-animals made up of sites and
• bond-animals made up of bonds.

• Polyominoes and site-animals are equivalent under lattice duality.
• There are a number of interesting subclasses of polyominoes (those highlighted in green have been solved exactly):

• One may also consider subclasses of bond animals (again, those highlighted in green have been solved exactly):