An intuitive software erector kit targeted at people new to programming, but with enough potential to stay useful once they've learned, inspired by HyperCard.
This would probably be an early form of the Project Canvas (#12) that shows all stacks at least, so you can open one, and see what stacks a project contains.
This would probably be an early form of the Project Canvas (#12) that shows all stacks at least, so you can open one, and see what stacks a project contains.