Light-Clock Diamond (robphy)
This is the fifth 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/
You can drag point P to change the velocity of the worldline (through O).
The light-signals from O reflect off of the worldlines-of-light-clock-mirrors [not shown] and and meet at the first TICK since event O.