Jay writes -
Here is an Arduino controlled Charliplexed LED heart just in time for Valentine’s Day. It uses a total of 6 wires to control the 27 LEDs. A PIC or AVR could easily be used for this, but I have Arduinos lying around and they are easy to program. Plus I want to be able to have input options later when I have time to write them.
Arduino charliplexed heart - [Link]