In this example, we will look at anticlockwise rotations, where the centre of rotation is the origin.
To see the effect in the interactive diagram below, click one of the buttons to rotate by 90°, 180° or 270°. You must click the reset button to return the shape to its original position before trying another angle.
If you wish, you can also move the shape to different position, by dragging the red point in the centre of the shape. You can then rotate it again to see the effect this has.