These are awesome and mesmerizing, even more so that they demonstrate what can be done with native browser WebGL APIs. Give them a try. (Warning: some may be quite laggy if you have lower end hardware, and I haven't tested these on mobile.)
Ever wanted to paint realistic-looking brushstrokes in your browser? You're welcome.
An interesting look at what's possible with WebGL these days. The graphics aren't as detailed as they could be, but I suspect that's more to make it run smoothly on lower end hardware than a limitation of the technology. More information in the source link below.