New wooden marble run! Build it with 294 pieces and 10 marbles. The end result is pretty cool. It has a crank that uses large gears to move marbles up to the top of the machine where they roll down into different channels. Different from other wood puzzles, black-grey appearance, metal nameplate and acrylic pieces to make the finished product more visually interesting and allowing the balls to be seen in action more. Great instruction booklet with big and detailed pictures makes it easy to identify the parts and makes the instruction clear. There is one spare parts sheet in case you broke critical pieces during assembly. Also you can contact us anytime. It's a great alternative when you've tired of jigsaw puzzle. This one was more advanced. This marble run model can be put on a bookshelf and believe that your friends will always ask you what it is and want a demonstration. This STEM puzzle will be outstanding Christmas or Birthday gift for those who loves to work with wood and loves a challenge, not only for teenagers, it will take around 7 hours' concentration to assemble properly.