In this video, five-year-old Jensen is intent on building stacks made of heavy automobile tires. Notice how Jensen marks the intended use of one of the tires. Knowing that she has to leave to get a tire to stand on, she leans the tire to be lifted against an existing stack. She rolls another tire close to the stack and then begins to heft the waiting tire. While leaning the tire may seem like an insignificant detail, she has in essence said, “This is not the tire I will stand on, but rather the one that I will lift.” Perhaps Jensen anticipates that when she gets two tires side by side, it might be difficult to know which one she intended to lift. Children not only solve problems; they also invent strategies for solving them more effectively as they play.