Related: The MGR Window System https://hack.org/mc/mgr/

“MGR provides each client window with: curses-like terminal control functions, graphics primitives such as line and circle drawing; facilities for manipulating bitmaps, fonts, icons, and pop-up menus; commands to reshape and position windows; and a message passing facility enabling client programs to rendezvous and exchange messages.”

Essentially, each window was a souped up ASCII terminal with extra escape sequences which implemented primitive graphics. It competed with X-Windows on low-end workstations during the 1980s.

Discussion: https://news.ycombinator.com/item?id=18742611