Playground is just another form of REPL. For example, here are two forms of of the same exercise, the firt one running on iPad, the second in Docker/Linux: 1.

Playground is just another form of REPL. For example, here are two forms of of the same exercise, the firt one running on iPad, the second in Docker/Linux: 1. https://github.com/ontouchstart/swift3-playground/blob/39331a9e2ef115bc248daf1eba1db22bcd1896d0/playground2book/001/README.md https://github.com/ontouchstart/swift3-playground/blob/39331... 2. https://github.com/thinkswift/TS/blob/296775627b19c4d98eb7fdc19211a90d8e56ee95/001.md https://github.com/thinkswift/TS/blob/296775627b19c4d98eb7fd... My point is that there is a difference between mastering the toolchains and understanding the deep concepts. I totally agree that we have to start from somewhere concrete, quote Seymour Papart: "you cannot think about thinking without thinking about thinking about something". However, we should also "focus on the big picture and zero in on the powerful ideas ..." - http://news.mit.edu/2016/seymour-papert-pioneer-of-constructionist-learning-dies-0801 http://news.mit.edu/2016/seymour-papert-pioneer-of-construct...