How does console graphics work? (less curses, vi ...)

Question

Can someone explain to me how less vi and program curses control the graphical output? Can they change individual characters on the screen, or do they have to write literature and redraw the screen whenever something changes?

It would be really neat if someone could hack a tiny smaller clone together without the whole template.

Answer 1

There are special Escape Codes that, when sent to the terminal, instruct the terminal to move the cursor without disturbing the displayed one.