Reflect points [i]B[/i], [i]C[/i], and [i]D[/i] about [color=#1e84cc][b]point [i]A[/i][/b][/color]. Then, slide the slider to see another alternative way to describe what it means to reflect any object (point, polygon, whatever) [color=#1e84cc][b]about a point[/b][/color]. (Feel free to move points [i][color=#1e84cc][b]A[/b][/color][/i], [i]B[/i], [i]C[/i], and/or [i]D[/i] anywhere you'd like at any time.)