I got a couple of DigiRule's [0] from their kickstarter [1] a few years ago which was kinda fun. It has interactive logic gates, flip flops, a 4 bit counter and

I got a couple of DigiRule's [0] from their kickstarter [1] a few years ago which was kinda fun. It has interactive logic gates, flip flops, a 4 bit counter and a handful of different modes. On the back you get some truth tables and some common pads and size holes. Selling for $11 [2] [0] https://www.bradsprojects.com/the-digirule/ https://www.bradsprojects.com/the-digirule/ [1] https://www.kickstarter.com/projects/1897710270/digirule-the-interactive-binary-ruler https://www.kickstarter.com/projects/1897710270/digirule-the... [2] https://www.tindie.com/stores/bradsprojects/ https://www.tindie.com/stores/bradsprojects/