Concentric circles and lines always seem to catch my eye. They hold a lot of movement and tension and have an inexplicable beauty to me. This little morning project scripted in Processing draws a waving horizontal line. Each point on the line has a vertical speed and acceleration, and the line is recalculated fifty or so times.
To add a little more depth I put in a blur filter before each new line set, and an invert filter creates some nice complimentary colors.