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Love the build, and love the video, but there is something I can't quite wrap my brain around. I can see how you've set up your motors and belts, and I could see how they would move the carraige from left to right on the x-axis, but I can't see how it moves the whole gantry back and forth on the y-axis. I looked at the belt setup png, and i've seen this configuration before on a couple of different machines, but I just don't see how that works. Is there a better explanation, or a better video, or something to better illustrate how that axes work?