Like a flight simulator for systems. Drag components, wire them together, hit play, and watch real traffic flow through your system. See queues fill up, databases choke, and bottlenecks form in real time. Scrub a timeline to inspect any moment. Fix what breaks, run it again. That's how you go from knowing patterns to understanding systems. Export to PNG, Mermaid, or Python for your docs and repos. 7 blocks, 12 behaviors, AI that turns code or prompts into live diagrams. Free in your browser.