Exploring Reflections with Intersecting Lines
While the letter F is reflected twice here about intersecting line, the lesson can be implemented by a single operation. Check each box separately/together to learn about the coordinates relate the Pre-Image.and Image. What is the single operation which can emulate this double reflection?
http://www.maa.org/sites/default/files/images/upload_library/47/Crowe/GeoGebra_Activity_7.html by Cheryll E. Crowe, Eastern Kentucky University