On Sat 4 Feb 2012 we met at Madiera High School( In Steve Phelps' classroom)

We considered a couple mathematical questions:

1. If you walk up to a mirror do you see more or less of yourself?
2. When different people see the image of a particular point in a mirror does it occupy a particular location or does the location depend on the viewpoint?

We had great fun thinking about this using markers on a window and on the floors on either side of the window.

We all participated in and contributed to a demo of the 3d features of Geogebra5 (beta) that let us visualize the situation of a single mirror and object with multiple viewpoints. People made comments about projective transformations. We used 3d glasses to view the color shifted version of the Geogebra document and were all very impressed. (You've GOT to try this!)

We talked about twitter, got several folks up to speed on that technology (Luddite Steve Pelikan in particular) , and posted some 3d Geogebra images developed in our discussion of mirrors to twitter under tag #cinymathcircle

We returned to a discussion of compositions of line reflections in a plane and how one could use Geogebra to have kids investigate such compositions.