Whether you're working on a big presentation for work or school, interactive visuals always help win over an audience. Loopy, a free tool for making simulations, is perfect for that.
Trying to explain complicated systems or feedback loops of any kind -- economic, political, social, ecologic and so on -- is always easier with a visual. But you don't need any complicated software to make visuals like that any more. Loopy, from developer Nicky Case, lets you draw them up with your mouse, MS Paint-style, in your browser. In just a few seconds you can create a complicated simulation loop filled with input/output nodes using only a super-rough sketch.
Once you've drawn your nodes, you can label each one, connect them with either a "+" or "-" relationship line, and add text around everything to explain what's happening. If you mouse over a node, you can click to increase or decrease the number of arrows moving through your loop, adjusting your simulation on the fly. The animation above shows off how it works. In this scenario, the more rabbits there are in the wild, the more foxes there can be. And more foxes means fewer rabbits. But that's just a very simple example of what you can do with the tool. When your simulation is complete, you can share the system model with a link, or embed them in websites.
You can learn more and give Loopy a go here.