The parts don't offer much flexibility in how the gears can fit together. Plates only allow a standard grid arrangement. The vertical pieces allow the gears to interact at right angles, but that doesn't work at all the way we'd like. Larger gears cannot interact with smaller gears via a grid of bearing plates - they just don't fit into that grid. You can just put a big gear on top of a small one, which looks fine in the pictures but actually doesn't affect the mechanism in any way. My son is four years old, he is five. He takes out this toy and tries to play with it. He really wants it to be as fun as it looks on the bucket. However, it just doesn't allow for enough mechanical creativity. You need to place the gears on the template provided, then essentially decorate them with (otherwise pointless) larger gears, lights, and feathers. Any sequence of more than four gears will simply overload and stop the engine. Because you can only place the gears in a very rigid column and row arrangement, the product is always mechanically uninteresting. Slinks and bulbs make it more interesting and active, but if I wanted panties and strobes I could get them without buying a bucket of poorly designed gear. another company, for juniors. Since these gears can be freely positioned relative to each other, this is actually a much more interesting toy. I would be interested in finding a version of this that is well designed and not well marketed.
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