One of the most irritating inconveniences is a table that wobbles back and forth when you lean on it. Assuming the cause is uneven ground, math proves that if you rotate the table, the legs will find a perfect resting place within a quarter rotation.
Instead of reaching for a coaster or piece of paper, mathematician Matthias Kreck from the University of Bonn explains to Numberphile how easy it is to fix your wobbly, four legged table with just a little maneuvering. The wobbliness is most often caused by uneven ground or flooring, and Kreck's proof shows that it's possible there are multiple "sweet spots"—or places where all four legs touch the ground—as you rotate the table.
Keep in mind, this strategy is most effective for four legged tables with just one problem leg, and can't be guaranteed if the leg is actually just shorter than the others. So, if the location will let you rotate your wobbly table, give it a twist to save the day.