The regular way you did graphics with a PDP-10 or 11 was
https://terminals-wiki.org/wiki/index.php/DEC_VK100
It had ANSI escape sequences equivalent to CIRCLE or LINE like you'd find in microcomputer BASIC except the Gigi was much more colorful than any early micro.
These are an interesting design, especially with the remote-terminal aspects. I do wonder how the CRTs were driven at that resolution.
This has now reached the masses with the sale of over 9000... I mean 800 PiDP-10 units. Oscar is kind of pushing ITS as the premier PDP-10 operating system.
Short thread at the time with some author comments https://news.ycombinator.com/item?id=17659799