A Galvagni figure is a figure that can be tiled by a polyform in more than one way—a kind of self-compatibility figure.
There are 607 heptacubes, or 1023 if we distinguish mirror images. This is too many to show here. Most require at most 4 tiles (with reflection), so they are fairly easy to find. Here are the Galvagni figures for heptacubes that require 6 or more tiles:
This heptacube has no Galvagni figure:
Last revised 2015-10-05.