Calculating a tip while sober can be taxing enough for some of us—but for those who like a challenge, there's always calculating a tip after a night at the bar. Closing a bar tab with a credit card is a delicate art that requires math, empathy and penmanship. And if the Close Your Tabs blog is any indication, things don't always come together as a drinker might wish. Each photo posted on the daily blog showcases yet another bar patron's drunken liberties with numbers and writing. Most demonstrate failures to add properly, and some even subvert our expectations with totals that shrink after the tip is added. Some are reminiscent of Jackson Pollock's finest works. Others are incredibly simple, although their meanings may remain elusive. After all, it's tricky to comprehend artists' intentions when the artists themselves are barely conscious of their own intentions. But every piece does come with a crystal-clear underlying message: try to close out your bar tab before you've had a few too many.