Variable Compression Ratio Single Cylinder Engine

https://www.youtube.com/watch?v=JnUXYR0LcfU
The variable compression ratio engine isn't a new idea, but Nissan says they're actually going to build this design, so it's probably worth figuring out how it works. What better way than building a physical model yourself?
Of course, this model and this shiny official video https://www.youtube.com/watch?v=3rn-gZNJBIU didn't exist yet so I didn't really have that option. I watched the Engineering Explained video, but still found myself wondering "OK does that part spin or rock or what?" I thought I had remembered seeing an official gif here https://web.archive.org/web/20150509071252/http://www.nissan-global.com/EN/TECHNOLOGY/OVERVIEW/vcr.html but there isn't one. I ended up just studying this video https://www.youtube.com/watch?v=PIWYoWvyE4s which thankfully got it right.