This article is 10 years old but it’s new to me. Discovered it looking up the origin of Easter eggs.
https://www.nationalgeographic.com/science/phenomena/2010/03/01/an-60000-year-old-artistic-movement-recorded-in-ostrich-egg-shells/
An 60,000-year old artistic movement recorded in ostrich egg shells
SOUVENIR SHOPS IN South Africa are full of lamps made out of ostrich eggs. The eggs are so big and strong that you can carve and cut intricate designs into their shells. The egg’s contents are emptied through a hole and a bulb can be inserted instead, casting pretty shadows on walls and ceilings. The results are a big draw for modern tourists, but ostrich eggs have a long history of being used as art in South Africa. The latest finds show that people were carvings symbolic patterns into these eggs as early as 60,000 years ago.
Pierre-Jean Texier from the University of Bordeaux discovered a set of 270 eggshell fragments from Howieson Poort Shelter, a South African cave that has been a rich source of archaeological finds. Judging by their patterns, the fragments must have come from at least 25 separate eggs, although probably many more.
Texier says that the sheer number is “exceptional in prehistory”. Their unprecedented diversity and etched patterns provide some of the best evidence yet for a prehistoric artistic tradition. While previous digs have thrown up piecemeal examples of symbolic art, Texier’s finds allow him to compare patterns across individual pieces, to get a feel of the entire movement, rather than the work of an individual.
As you might expect, the millennia haven’t been too kind to the shells but even so, their etchings are still well preserved and Texier even managed to fit some of the pieces together. Despite the variety of fragments, their patterns fall into a very limited set of motifs produced in the same way – a hatched band like a railway track, parallel(ish) lines, intersecting lines, and cross-hatching. It’s possible that, once assembled, these elements would have combined into a more complex artistic whole but Texier notes that he has never found a piece with more than one motif on it.
(More at link)