Site owner Matthias Wandel explains,
"If you are somebody who is into woodworking or construction, its good to be one of the people who notice when things are crooked. But I suspect the ability to notice that things might be just a little off square, off centre, or not quite straight, varies greatly. I thought it would be fun for people to try to test their abilities to see if things are straight or crooked in a little game."
You cycle through the seven challenges three times to generate an average, which becomes your score. Do well enough and you'll enter your name in the top 10 of the last 500 games, appearing on the front page.
So, targets people. I'm most pleased with getting a 0.0 twice in a row, the same game resulting in my current best score, 2.40. No cheating with set squares on the screen, and post your better scores below. Clearly (non-offensive) insults are the correct way to enter your name if you get in the Top 10. Big thanks to Kim for the tip.