First of all, I want to emphasize that HACK PACK is a great idea for the younger generation to create a bridge between watching Marek's videos on YouTube and really starting to work with technology. My son and I have experience so far with building IR TURRET and DOMINO ROBOT and we are already looking forward to the next one. We went through minor complications with both boxes (IR TURRET we had to ask for a new servo motor, with DOMINO ROBOT we had to rethink the principle of chassis connection in its rear part), but we take this as part of the philosophy that failure is part of the learning process. Your support for HACK PACK works great and that is why I would recommend it to everyone interested in technology. I am attaching a picture of the new chassis connection solution for DOMINO ROBOT, if it is useful to you and I wish you much success with your other ideas.