To give some more interest to the board, I used air drying clay and impressed a diamond plate patter into it with a roller.
These sheets I then placed onto the board. After the clay started curing, the edges curled up. I bent them down again, then glued the areas down with fast drying PVA, and they stayed flat after that.
For some broken ground, I mixed black pigment, PVA glue and diatomaceous earth into a paste, and applied it with about the same thickness to the board as the air drying clay pieces.
