Pixel Spirit is an interesting way to learn GLSL. Using a method of tarot cards, can show the input code & the output image. It’s really nice.
Originally created by Patricio Gonzalez Vivo, who is also the creator of the fantastic website The Book of Shaders, which helps in learning about Fragment Shaders in a great way.
You need Kode Studio, then simply drag & drop the project folder into it & run the project.
You can grab a pack. It’s limited, so get in touch with the creator to see if there will be another release. Head to Pixel Spirit Deck