1. A method comprising, by a computing device: identifying a gesture made by a user of the computing device with respect to one or more surfaces of the computing device, the gesture comprising a single trajectory in three dimensions including: an earlier portion of the single trajectory in a first direction along at least one of the surfaces, the earlier portion comprising a first series of points touching the at least one of the surfaces; and immediately following the earlier portion of the single trajectory, a later portion of the single trajectory in a second direction, the later portion comprising a second series of points distant from the surfaces, wherein the second direction comprises a deflection from the first direction that follows through on the earlier portion of the single trajectory; determining a user input based at least in part on a speed of the gesture along the earlier portion of the single trajectory and a speed of the gesture along the later portion of the single trajectory; and executing one or more actions based on the user input.