Alice's Longitudinal Light-Clock (robphy)

This is the third of six GeoGebra files (from my GeoGebra book Relativity on Rotated Graph Paper (robphy) - MAA2016 ) that were part of my MAA MathFest 2016 talk "Introducing Spacetime Geometry: Relativity on Rotated Graph Paper". http://www.maa.org/meetings/mathfest/program-details/2016/themed-contributed-paper-sessions It describes aspects of my paper “Relativity on Rotated Graph Paper”, Am. J. Phys. 84, 344 (2016); http://dx.doi.org/10.1119/1.4943251. An informal introduction is presented at https://www.physicsforums.com/insights/relativity-rotated-graph-paper/ Check "animate" to start the animation.