Find all points where the function is discontinuous.

A coordinate system has a horizontal x-axis with tick marks at negative 2, negative 1, 0, 1 and 2, and a vertical y-axis that has a tick marks at 0 and 1. A curve begins in the third quadrant and rises at an increasing rate to the point (negative 2, 0), then falls at a decreasing rate, is horizontal as it crosses the negative y-axis, then rises at an increasing rate to the point (2, 0), then falls at a decreasing rate in the fourth quadrant. There are open circles at the points (negative 2, 0) and (2, 0), and a closed circle at the point (2, 1).