I actually thought you were talking about this: <a href="https://www.circuitlab.com/" rel="nofollow">https://www.circuitlab.com/</a><p>I just came across it the other day, and though I haven't played with it a ton yet, it seems like an extremely useful tool for learning about electronic circuits.
Delightful. I made this!<p><a href="http://www.neuroproductions.be/logic-lab/index.php?id=9342" rel="nofollow">http://www.neuroproductions.be/logic-lab/index.php?id=9342</a>