The physical game board has 5 irises staggered at the bottom. The irises will open and close by the use of servos working behind the game board. A processing sketch is projected onto the board with circles in positions corresponding to each iris.
Particles/balls/objects fall from the top. The objective of the game is to catch these objects by opening the irises. To open an iris, the player presses the button on a physical controller, which triggers the servos. Each iris will only stay open for 2 seconds then closes again. If the object hits an open iris, player scores a point (iris lights up/blinks). If it hits a closed iris, it will bounce off and change its vector. At that point, the player still has the chance to catch it by opening one of the irises in the next row. If the object is never caught, it falls off the screen and disappears.
It sounds like a fairly simple game, but because of the timing, it takes quite a bit of skill. Sometimes it is best to catch one in an open iris, but other times it is best to bounce the ball off a closed iris and catch it in an open one.