Paint to color and seal 10 cinder blocks with black high-gloss paint. Let dry overnight.
Arrange the blocks in the desired space with two rows of four cinder blocks, with a single cinder block in between the two rows at the top and bottom. Place all blocks with the hole sides down.
Apply heavy-duty construction adhesive on the top of the corner blocks. Then center and top the cinder blocks with the piece of 3/4-inch oak plywood.
Finish the project by painting the plywood with black high-gloss paint (or whatever color you prefer).