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: In this vanilla rendering of temporally dense ray tracing, we simply ray trace one out of every four pixels each frame and reuse the remaining pixels from the previous frame. As can be seen, the quality of high frequency edges (geometrical, texture, and shading) tend to break down. We show these images as proof that some kind of clever filtering is needed to get acceptable quality.

Desired frame rate: