Around the same time as when I was working on the Teachable Machine installation, I was also asked to help prototype an experience that revolved around the idea of a slideshow where users could have enhance presentations online. The idea was essentially to add a bunch of little effects that would get triggered through various commands, including the one I helped build around the idea of a "virtual laser pointer", for lack of better words.

The idea was basically to allow the user to hold down and draw lines that would fade out after a few seconds. For the most part it worked, but there remained issues with how HTML canvas handles transparency that I wasn't able to solve.

You can see a test setup here