The Change button will cycle between the available transforms. The currently selected transform and the corresponding iteration equations will appear on the Transform Control Panel, accessible through the TCP button.
Also the active transform name appears in the margin at the top of the display. If we iterate either of these transforms, a trajectory will be traced out on the screen from the initial point. Just to illustrate the effect of each transform alone, run the Selectable Transform - Spin or Shrink + X Displacement display, clicking the Action button 8 or more times. You will see that the only points on the screen reachable by the Spin transform are the eight points of an octagon including the initial point.
Next click the Reset button to reinitiate the display and select the Shrink + X Displacement transform by clicking the Change button, invoking it numerous times with the Action button. All you will get is a line of points converging on the point 10,0.