In described examples, a microelectromechanical system (MEMS) includes a first element and a second element. The first element is mounted on a substrate and has a first contact surface. The second element is mounted on the substrate and has a second contact surface that protrudes from the second element to form an acute contact surface. The first element and/or the second element is/are operable to move in: a first direction, such that the first contact surface comes in contact with the second contact surface; and a second direction, such that the second contact surface separates from the first contact surface.