A cup isn't very tall. But what about a lot of cups? This "Fetch!" challenge is to build a tower just made out of cups. How high can you go? Remember, the sky's the limit! Gravity - a tower's worst enemy? Maybe. Gravity can make a tower fall. But it also holds the cups in place! The trick for surviving gravity's pull is to distribute the tower's weight properly. For example, a wide base spreads the weight over a broad area, helping to keep a tower stable.