When you tweet at Moody Bot, it studies your posts, analyzes your personality, and then draws a picture for you.
Moody Bot uses IBM's Watson. This analysis provides the seed for generating a unique image, which is then posted to Moody Bot's Twitter feed.
The bot is a Node.js script that is scheduled to check for new mentions on a regular interval. The code that generates the image is inspired by the superformula.
Moody Bot is just getting going. Check out the Twitter page to see what it's been up to.
This is how the various pieces fit together.