# Galvagni Figures & Reid Figures for Polybirds

A *polybird* is a plane figure formed by joining adjacent cells
on the
rhombitrihexagonal grid.

A *Galvagni Figure* is a figure that can be tiled by a polyform
in more than one way—a kind of self-compatibility figure.
Galvagni Figures first appeared in Erich Friedman's
Math Magic
for November 2004.
A *Reid Figure* is a Galvagni Figure with no holes.

Here are minimal known Galvagni Figures for polybirds with 2–5 cells.
Minimal known Reid Figures that are not minimal as Galvagni
Figures are shown separately.
If you find a smaller solution or solve an unsolved case, please write.

### Impossible

### Impossible

### Reid Figures

### Impossible

Last revised 2021-11-06.

Back to Galvagni Compatibility
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Polyform Compatibility
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Polyform Curiosities

Col. George Sicherman
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