Note: this has only been tested on Firefox browsers -- Chrome works, but does not always reach 240 Hz.
Supplemental website for the HPG 2019 short paper: Temporally Dense Ray Tracing by Pontus Andersson, Jim Nilsson, Marco Salvi, Josef Spjut, and Tomas Akenine-Möller.

Hang on, measuring monitor refresh rate...

Explanation: This is the same set up as in the static edge test. Notice how the viewing experience suddenly becomes pleasant when switching to 240 Hz, compared to that of sub 240 Hz, with significantly less noticeable crawlies.

Desired frame rate: