This hole in the center will act as a drying channel. If you want a broken pillar, put it into a plastic bag and hit it with a hammer. What's in the bag will be your rubble. Remember, only paint Durhams with acrylic paint. Using a brush, no matter how good it is, may not yield the desired results.
Styrene plastic is a good medium for making pattern tools.
Diamonds or squares can be made from various sizes of commercially available styrene. By having smaller and larger sizes of the same shape it is easy to overlay multiple colors. Circles, from the smallest dot can be made from stretched sprue or commercially available styrene stock. Very small dots could be used to enhance larger designs or grids on clothing. If the larger designs are going to be painted by brush, try using a liner brush as it holds more paint and allows a one stroke application.