The user will interact with the concrete table's constellations by placing an RFID tag upon the surface of the table. Imbedded in the concrete is the antenna for a parallax RFID reader connected to an Arduino. The Arduino will set the assigned pins for each constellation high when the a specific constellation's card is layer down.
As I was a kid, I have seen similar device at Gorbushka market at Moscow. It was a vertical black piece of wall, displaying animated galaxies. And I was wandering of the existence of the light bulbs as small as 1.0 mm, that can change colors on-the-fly.