“Back in the day, we had to create everything by hand,” Nintendo designer Takashi Tezuka said in a video released as part of Nintendo’s E3 announcement Tuesday. Every square of land, question-mark block and Goomba had to be hand-drawn and colored on graph paper. When they were happy with the design, they sent it off to a developer to code. Fixing errors or making changes was tricky. Shigeru Miyamoto, Mario’s creator, said whiting out mistakes was too messy, so they overlaid opaque tracing paper on top of the level being drawn.
Be sure to check out the embedded video starting at 41:11.