Geogebra can be used to teach many mathematical concepts. One of them that Geogebra can help with is the reflection of a polygpon. Geogebra makes it easy to draw polygons and choose points and lines to reflect over. The website is easy to navigate and the program is free. I have attached a worksheet with step by step instructions about how to construct polygons using Geogebra and how to create lines or points that the polygons will be reflected over.