We've discussed how to learn to code before, but Blockly combines the simplicity of a good set of instructions with the intuitiveness of a jigsaw puzzle. The idea is to give beginning coders an idea of what commands can be written and how they're placed together, without making them worry about learning the terms by heart or closing brackets. For more advanced programmers, it could also be used to mock up small programs in an unfamiliar language or API. Blockly is a successor to Google's App Inventor, itself inspired by MIT's Scratch, but it has some new features, like the option to export your blocks as real code. At the moment, it's still in the developer preview stage; you can try out one of the demos here to practice building your own blocks in the browser.
Google Blockly: an easy, visual way to learn to code
Google Blockly: an easy, visual way to learn to code/
Blockly is a jigsaw-like tool made by Google to teach beginning programming skills.