I've already built ping-pong machine with 51515, and i can't wait to test it. Next friday i'll demonstrate your project to my students (primary school). Litlle feedback: on 110 step you used Liftarm Thick 1 x 3 to mount 2 black liftarms, but it doesnt work, they just spin around, but in yt movie i saw Axle and Pin Connector Perpendicular 3L with Center Pin Hole insted Liftarm Thick 1 x 3. 51515 contains only 2x Axle and Pin Connector and your build need 3 of them. Final note so far: 10/10 just love the ping-pong project! Greeting from Poland :)

We are so excited, we can not wait to test and having fun! Thank you, you are doing a good job! 😃