At first you may be wondering what the smurf that thing is, and you’d be correct in doing so, because it’s weird looking. You may think it’s a strange cup holder or perhaps a stylish engagement ring for nerds, but you’d be wrong. In fact, you were very wrong. It’s actually a device that supposedly aids in drawing perfectly straight lines with any writing implement. The following pictures explain the concept quite well. I’m dubious of the fact that simply because there’s a wheel it can only move in one direction. However, using it as an odometer to calculate the drawn distance is a neat feature, regardless of how straight the line is.
More pictures and words at designboom.