Technically, I guess you wouldn't say ASCII because the ASCII character set doesn't have graphical characters.
But on the IBM PC running MsDos as well as platforms such as the CommodoreAmiga or CommodoreC64?, you have a number of graphical block characters available for sprucing up otherwise bland text displays.
I used to use the BlackBeard editor to do my drawings. Everything from simple screen mockups to flowcharts (and they were old when I was in college) can be done with these techniques.
Editors which I know can do this include:
Emacs has PictureMode? but it is pretty lame as I recall. It is basically just a form of UnboundCursor? movement. That is, the cursor is not constrained to move within the characters in the text but can go past the end of lines, treating the screen as a canvas.