Hi-Res | Classic retro game for the Commodore PET Computer (1980)

HI-RES uses clever timing tricks to create a small pseudo-high-resolution region measuring 9x5 character cells at the top of the screen. The program changes the character in every cell before the PET draws each scan line, so for example, you could have the top half of the letter H combined with the bottom half of the number 8, or any other arbitrary combination of characters in a given cell. In this way, it becomes possible to place any pattern of dots in the hi-res region, provided that pattern of dots is present in a byte of character ROM at the correct horizontal line within some character glyph.