Also a good basis for making Warhammer and other gaming terrains
Step 1: Supplies
Styrofoam insulation board (Only because it is very fine grained and is easy to work with)
Plain Clay Cat Litter (unscented or any "extra" additives)
Sawdust (everything has a use) or if you want to buy static grass for model railroads.
Toothpicks (round ones are better)
Thin cardboard or card stock
White Glue (like Elmers)
Paints: Black, Gray, White, Green, Blue, Yellow other colors are optional.