I thought I had uploaded this back on the 12th, but apparently not.
These are the paths created by my mouse as I worked throughout the day. The larger, darker spots are where my mouse rested. I was doing some coding that day, and when I work in TextMate I have its window on the right side of my screen, which would explain why the mouse was resting often near the left/center of the screen.
Also, that big blob toward the left apparently means I ate lunch that day. For once.