I got this idea off http://fun.kyti.me/
I changed it a bit for fun, and I have just come up with an idea to use different colored plaster for different layers in different colors.
What you need:
Plaster
Some old candles
A few paper cups
& water
STEP 1: Mix up your plaster and add water until sloshy like a smoothie, then pour into the paper cups.
STEP 2: Push in the candles and leave to dry until firm like a rock.
STEP 3: Once dry, paint in stripes, spots, patterns or anything else and use. To change candles, melt the candles down to wax and place the other candles in.
HAPPY CANDLE MAKING!