High-res graphics on a text-only TRS-80

From the Byte Cellar:

What inspired me to pull the Model 4 down off the shelf were a number of tweets from telnet BBS pals showing the system being put to great use logged into various systems across the web. Some of the screenshots showed the machine rendering ANSI "graphics" onscreen and I looked into it. As I suspected, the stock Model 4 is not capable of taking on a custom character set such as is needed by ANSI emulation, and I discovered the system had been equipped with a graphics board and the ANSI-supporting terminal program, ANSITerm, was rendering "text" to a graphics display; the character set was basically a software font.And I just had to go there.