Original Super Mario was designed on graph paper
The first Super Mario game released in 1985. It was designed by hand on graph paper.
"Back in the day, we had to create everything by hand," says Nintendo designer Takashi Tezuka. After drawing every detail on graph paper, the designers sent the drawings to the developer to code. Fixing errors after that point was very difficult. Mario's designer Shigeru Miyamoto said that whiting out mistakes was messy, so instead, the designers overlaid tracing paper over the the level being drawn in order to make edits.
Cover image: Quartz