Alligator clips, ball joints, set-screws and a bigass magnifying glass all clamped to a cast-iron base. In the hand, it feels like a torture device. On the windowsill it looks like an orrery of mechanics, its arms and clips perched in frozen orbit around the empty spaces of the work it should be holding for your eyes - the tying of flies, the soldering of tiny circuits, the painting of trolls' eyebrows with a single-hair brush.