They are named after Andy Liu's puzzle pieces Birds and Bees. Birds and Bees is a trademark of Kadon Enterprises, Inc. See also Catalogue of Polybirds.
A Baiocchi figure is a figure formed by joining copies of a polyform and having the maximal symmetry for the polyform's class. For polybirds, that means the symmetry of a regular hexagon, or 6-way rotary with reflection. Claudio Baiocchi (1940–2020) proposed the idea in January 2008. Baiocchi figures first appeared in Erich Friedman's Math Magic for that month.
Here are minimal known Baiocchi Figures for polybirds of orders 1 through 5. Baiocchi Figures for polybirds must conform to the grid.
Not all these solutions are uniquely minimal.
By convention, polybirds may not be reflected (flipped over). In these figures, they may be flipped. Polybirds in black have no Baiocchi Figures.
Thanks to Mark Smith for suggesting these.
Last revised 2021-11-03.