What's p5.js?

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The third option is to use one of the text editors e.g. Sublime, Atom, Visual Studio Code and run p5.js directly on your computer. For that you would need to download a complete p5.js library and run the code on a local server.

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References:

In order to understand the examples and to write your own programs, you will be using references, i.e. artifacts  artefacts that describe a programming language.