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MAKE Flickr photo pool member Oskay writes – “Detail photo of Gravitram One at OMSI in Portland, Oregon. This is an amazing rolling-ball kinetic sculpture that has been running approximately continuously since 1973. It’s made (mostly) of 1/8” diameter copper-coated mild steel welding rod, brazed together in a simple, yet remarkable fashion. You could watch this thing for hours. “Link.

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Gravitram sculptures – Link.