What you cant see: if you place something in the corners of the table, LDRs notice that and a red LED starts to be on in the corresponding corner of the LED part of the table.
The glass is coated with a special light scattering film and the LED have a special distance for perfect illumination of the squares. Those are arranged like it is shown in the picture - per 3 LEDs one square. The table is stained wood and also selfmade.
The whole table works perfectly fine and looks very cool!