Programming languages

https://en.wikipedia.org/wiki/Recursive_data_type interesting, no pointers.

Algebraic data types

https://en.wikipedia.org/wiki/Algebraic_data_type TODO why is the concept useful?

Why does C not have them through struct and union?

http://programmers.stackexchange.com/questions/159804/how-do-you-encode-algebraic-data-types-in-a-c-or-java-like-language

Go

Vs other garbage collected languages:

https://www.quora.com/Why-do-a-lot-of-people-hate-Java-but-advocate-Golang-Go-Language

Scratch

https://en.wikipedia.org/wiki/Scratch_(programming_language)

Educational, visual. Really good.

File format for 2.0 is a zipped JSON: https://wiki.scratch.mit.edu/wiki/Scratch_File_Format_(2.0) but apparently it does not look much like the visual representation.

Hardcore projects:

Doom-like FPS https://www.youtube.com/watch?v=XQT3j2RA-0g