I spent yesterday in my kitchen making variations on Jello. My current project is to discover the best combination of ingredients possible to give me maximum structure, shortest setting time, best release, most vibrant color and an appropriate degree of wiggle.
The chemistry of Jello is actually pretty fascinating. If you've ever wondered what makes Jello wiggle it has to do with the triple-helix structure of the polypeptides that form the collagen and how they trap water.
My tests involve a combination of ingredients including not just Jell-O® brand gelatin but also Knox® Gelatine, Jell-O's clear tasteless and less flashy cousin and my new favorite additive as it lends a superior solidity and firmness to the molds.
The other ingredients are in flux but I'm excited about my experiments. It remains to be seen how they will hold up outside.
Since the idea is for them to gradually deteriorate it's okay if they aren't bomb-proof but they need to maintain a degree of structural integrity for most of the day.