ok . pay attention now ! cut and plane some strips of wood of 3 different colours , mine were about 35mm wide, 5mm thick . set the chopsaw to 30 degrees . make first cut, then set the length guide so the next cut creates a perfect diamond shape. now you can cut a few at a time, cut loads ! glue them to a bit of 12or15mm ply,whatever, then once you've covered enough of the ply, use your Festo plunge saw to cut your top out, then frame it with a mitred edging strip.
easy mac peasy !