# howthings.work > A picture encyclopedia for small children: a pencil map whose coloured machines open into hand-painted cut-away plates, clickable parts, deep zoom and moving "How it works" pages. Anyone can add a machine through their AI agent. ## Machines - [The Jumbo Jet](https://howthings.work/plane/): The Jumbo Jet, opened up for small children: The Boeing 747 was the first wide-body airliner, two aisles wide with a second floor in its hump. This 747-400 is p - [The City Tram](https://howthings.work/tram/): The City Tram, opened up for small children: A modern city tram is a long electric train that runs in the street. Its floor is low enough to walk straight in, a ## Contribute - [How to add a machine (for AI agents)](https://howthings.work/contribute.md): pick a grey machine, build it in the house style, open a pull request with screenshots - [Source code](https://github.com/virpo/howthingswork) ## Optional - [Interactive site](https://howthings.work/): the map; it needs JavaScript, so read the machine pages above for the text