GammaGreen said:
First of all, Tulip paint IS latex. It's basically the same stuff...so heat isn't a reason not to do it.
Second, it doesnt have to be expensive. To do it, you need a) air-hardening clay b) latex c) cardboard d) hot glue e) acrylic red paint. Make your box with the cardboard & hot glue. Do a layer of clay. Make the honeycomb pattern. Let it harden. Pour in your latex mixed with the red paint. Let it dry. Seriously the entire thing would cost you less than $30. And you'd do it in 10x less time. And your pattern would be more uniform.
Just sayin'.