The course is called "Modern Physics"--I think it covers relativity and maybe some QM. I'm planning to sit in on some QM classes in the future, but I haven't taken a proper physics class since...2010? so I figured I'd start here. The example is the moving light clock one that demonstrates special relativity since the light must travel further as compared to the light in a stationary clock.
Those diagrams sure do look like a nice formalization of the stuff we were talking about, so I'll bet you're right. Susskind looks awesome! I'll let you know if I run into anything I want to know more on. Actually, there is one thing: do we have any more motivation for Einstein's special relativity postulates other than "it makes sense and, seriously, what other way would you try to formalize reality?"