Hey Product Hunt 👋 I'm Bolt Guo, and VizLearn started as a tool for one very specific person: me, trying to actually understand algorithms. Every explanation I found was either a wall of text or a static diagram. The few animations out there ran on someone else's data, at someone else's pace — I'd watch a sorting GIF five times and still couldn't answer "okay, but what happens if the array is already sorted?" Because I couldn't try it. So I built the thing I wished existed: a place where you don't watch an algorithm — you drive it. In VizLearn, every lesson is a hand-drawn animation, the source code, and an execution log that all move together — frame by frame, line by line. The part I care about most: you change the data and run it on your own input. Swap the array, set your own learning rate, pick a different hash function, then pause, rewind, and step through it while the exact line of code lights up. What's in it today: - 30 interactive lessons across Foundations, Algorithms, Data Structures, AI & CS — from execution tracing to backpropagation to the TCP handshake - Draw a digit and watch a real neural network classify it, live (MNIST) - Config panels on every lesson, so each one is meant to be poked at, not just watched - Scrub/step timelines for algorithms, real-time modes for data structures - An Explain doc beside every animation, 3 UI languages, and no sign-up required The hand-drawn look is on purpose. It makes the product feel closer to a professor sketching on a whiteboard than a polished black box, which is exactly the feeling that made hard ideas finally click for me. What's next: more graph algorithms, transformer internals, diffusion-model walkthroughs, and deeper systems lessons. I'd genuinely love to hear what confused you, what felt off, or what you'd want visualized next. There's a feedback button built into every lesson — tell me what to build next.