What the Circle Says

Two ions in a trap at Oxford, and between them, a square no bigger than four words: two sites where a little motion can sit, two links that say plus or minus.

The motion hops, and every hop goes through a link. There is no wall around a field it stays out of. It touches the field the whole way round, one link, then the other, and no single link is wrong.

Ask either one what it holds and the answer depends on how you write it down. Only the loop answers the same way every time. Set the loop to nothing and the motion crosses. Set it to a half turn and the two ways round arrive out of step and undo each other, and the motion stays where it started.

Nothing was hidden in the middle. Nothing reached across a distance. It was in every step and no step alone, the way a road can be fine at each bend and still not take you anywhere until you see the whole of it.

So stand still, then. It isn't a punishment. It's what the circle says when it is closed.