These GeoGebra files were part of my MAA MathFest 2016 talk
"Introducing Spacetime Geometry: Relativity on Rotated Graph Paper".
[url]http://www.maa.org/meetings/mathfest/program-details/2016/themed-contributed-paper-sessions[/url]
My slides are available here (at the website of the session organizer)
[url]https://www.framingham.edu/faculty/smabrouk/Maa/mathfest2016/tcps9/[/url]
It describes aspects of my paper “Relativity on Rotated Graph Paper”, Am. J. Phys. 84, 344 (2016);
[url]http://dx.doi.org/10.1119/1.4943251[/url]
An informal introduction is presented at
[url]https://www.physicsforums.com/insights/relativity-rotated-graph-paper/[/url]
