This is a binary/decimal/hexadecimal counter. Binary (green) is above the bulbs; decimal (blue) and hexadecimal (red) are below the bulbs. Up arrow counts up 1; down arrow counts down 1. Right arrow counts up 16; left arrow counts down 16. Mousing on and off an individual bulb turns it on and off.
The idea for this project came from Bill Gates' 1996 book "The Road Ahead." In it, he describes a system with eight light bulbs arranged as shown here, from left to right, with watt values of 128, 64, 32, 16, 8, 4, 2, and 1. By lighting different combinations of the eight bulbs, you can produce any amount of light you want, in 1 watt increments, from 0 watts to 255 watts. Thanks to griffpatch for the text engine. A good explanation of binary and hexadecimal can be found here: https://en.wikipedia.org/wiki/Hexadecimal
