Q: How does the barrel mechanism operate, and how many barrels can it hold at once?
At its core, the barrel mechanism works like a pump. A vertical column of 14 barrels runs up the side of the LEGO model, and every pull of the barrel lever pushes a new barrel into the bottom of that stack while another drops out from the top. In total, the system can accommodate 20 barrels, which means up to six barrels can be rolling through the course at the same time.
Q: Do the barrels travel all the way to the bottom? Do they come out of the build and need to be placed back in, or does the mechanism send them back up automatically?
The barrels make the full journey from the top of the build down to the bottom, where they are gathered in a hopper linked directly to the barrel pump. That setup creates a continuous barrel loop, turning the LEGO Donkey Kong-style action into a self-contained cycle of, quite literally, barrels of fun.
Q: What proved to be the toughest part of designing and testing the barrel system?
The hardest part was making sure the barrels moved slowly enough to match the feel of the classic gameplay, but without stalling or jamming along the way. The solution came from a carefully tuned mix of small steps, LEGO studs, angled slopes, curved elements and LEGO Technic beams, which are just a little slimmer than standard LEGO bricks. Getting that timing right took a huge amount of trial and error—I sent thousands of barrels down those tracks during testing. By the end, those barrels were driving me bananas.
The next major challenge was figuring out how to return each barrel from the bottom of the model back to the top. We experimented with all sorts of ideas, including launch mechanisms, worm gears, force-multiplying levers and other elaborate solutions. In the end, the simplest and most effective answer was also the most obvious: use a lot more barrels.
Q: How do the joystick and button control Jumpman/Mario’s movement?
The joystick moves Jumpman from left to right using a long lever up the back of the model, connected to a dingler. The jump button uses a similar mechanism used in a piano key. When it is pressed down in front of the model, the other end of a see-saw lever presses up on a long rod with Jumpman at the top. When the button is released gravity returns Jumpman to the bottom.
