Easier than engraved egg and easily achievable by children.
The eggs are edible!
Paste stickers or pieces of vinyl.
Do not make too big shapes so that they fit tightly to the egg.
Soak the eggs 2 hours
(approximately, depending on your dye concentration).
Egg shells are porous and crystals formed, the dye is not uniform.
Look at the pretty pointillism of the green egg.
Paste stickers shifting them compared to the first bath.
Soak for 2 hours in a different color.
If you have used food coloring, you can eat the eggs.
You will have a surprise peeling them