Comment by brumar

I made a game of life in pdf using this technique, but pdf.js is less open to chromium to respect the standard on letting the pdf designer defining the ON and OFF state.

One other way would be to use normal text fields and leveraging custom fonts. I think there are an enormous potential with fonts in the realm of pdf hacking. I think there is also a story of past vuln on pdf.js because fonts were evaluated outside the sandbox.