Geodeseggs

<Authors note> I can't find anything to corroborate that this will actually work.

Making a traditional Easter egg is a wonderful thing.
You make two small holes in the shell, top and bottom, blow out anything edible and you are left with a small oval calcium canvas on which to create a geometric, wax and food coloring masterpiece.
This process has remained unchanged for hundreds, perhaps thousands of years, although they may have had a different name for them that far back.
So the notion is to take your empty eggshell and submerge it in a vinegar bath for a very specific but as yet undetermined length of time. Long enough that it has had enough calcium dissolved to be pliable but not long enough to have totally disintegrated. The bath itself to which the vinegar is added, is actually the mold, which when the vinegar is drained and the air is evacuated will cause the shell to warp into the molds' shape for the drying process.
Picture a spiral eggshell, a geodesic oval, or maybe a bunnies’ head shape. Now bake or let air dry until the de-calcified shell holds its shape and remove the mold.

The remainder of the Easter egg coloring experience would remain unchanged but the end result sure wouldn't, why they might even eggspand into other holidays.