Suppose you have a light spring stretched out and one end is attached to a wall. With this setup, you can move the free end in any of three directions \((x, y, z)\). If the spring lies along, say, the \(z\) axis, which type of wave-transverse or longitudinal-do you create when you move the free end along the \(z\) axis? Along the \(x\) axis? Along the \(y\) axis?