If you want to get into fixed-width character art, I highly recommend doing it in the browser like OP did rather than trying to old school it in the terminal. I have done a little ascii[0] and unicode[1] graphics, and the browser is such a better tool. You can set fonts and proportions and know exactly how things will render for the user. Mouse input, performance profiling and a bunch of other things are just better…
Command line tools (and by extension TUIs) can be used over SSH and don't require messing around with HTTPS certificates. They also have the benefit of having the context of your CWD.