The Circuit Scribe aims to make building circuits as easy as doodling, and while a single pen will only set you back $20, an extra $10 will net you a pile of other resistors, capacitors, batteries, and switches so that you can start building stuff right away. There’s even a $100 package with dozens of extra components like sound buzzers, photo sensors, and a motor. To be sure, the Circuit Scribe's silver-water-cellulose mixture isn’t the first conductive ink product on the market, but judging from the video above, it looks a lot nicer to work with than some of the alternatives out there.