About Codesarray

Codesarray makes calm games for Android, and teaches programming through short videos and written lessons. The lessons come first on this site: each one explains a single idea, shows real code, and prints the real output.

What you will find here

• Lessons. Written articles for Python and JavaScript, filed by level: beginner, intermediate and advanced. Each article goes with a video of the same name on YouTube, so you can read it, watch it, or do both.
• Short notes. Small articles that explain one surprising behaviour, such as why a Python int never overflows, and point to the full lesson it belongs to.
• Games. Three games for Android: Blockfall, Paws & Perils and Synapsy. They play offline, with no accounts.

How the lessons are made

Every code example in a lesson is a real file that was run before it was written up. The output you see under it is what the program printed, copied exactly. If an example could crash on an input the lesson's claim covers, it is changed or the claim is narrowed before publishing.

Lessons teach the current versions: Python 3.14 and Node 24. When a feature is new, the lesson says which version added it. The videos are drawn with code rather than recorded from a screen, and the narration is written first, so what appears on screen matches what is said.

Lessons go in order, one idea at a time, each building on the ones before it. Plain words come before technical ones, and a lesson ends with the questions a learner at that point tends to ask.

Corrections

If a lesson is wrong, unclear, or out of date, please tell us with the page address and the line in question. Mistakes are fixed on the page itself.

Who makes it

Codesarray is an independent developer's studio. Background and experience are on the Work page. The site has no accounts, no comments and no tracking of its own; see the privacy policy for exactly what that means.

Advertising

The lessons are free to read. The site may show ads through Google AdSense. Ads never change what a lesson says, and nothing on the site is sponsored content.