A fork of my blocklib code from Architecture of Open Source Applications: 500 Lines or Less http://www.aosabook.org/en/500L/blockcode-a-visual-programming-toolkit.html to make this code more easily re-usable and to fix issues like drag-and-drop not working on mobile. Still tiny and relatively comprehensible, the text of the 500 Lines book should still be a good guide to understanding the code.
The goal of this tool is to show how to build a very simple block-based visual programming language suitable for re-use.
Drag-and-drop using the Dragula library created by Nicolás Bevacqua.
Turtle Image by Clker-Free-Vector-Images from Pixabay
Some code and much inspiration comes from my own Waterbear project, which is a larger and more full-featured tool for block-based code.