Stacks runs original HyperCard stacks directly on a current Mac without an emulator standing in between, so the clickable cards, buttons, and scripts built in the 1987 authoring environment behave the way they did on the original hardware. HyperCard was the tool a generation of non-programmers used to build their own interactive software, and Stacks makes those decades-old files openable and usable again instead of stuck as museum artifacts.