A Click in the Quiet

I... I stared at the ridged black wheel wedged right between the two smooth halves of the giant plastic dome. It sort of looked like a miniature motorcycle tire. I paused for a long time, listening to the quiet room and wondering if it was a trap. Slowly, I reached out and tapped the rim with my hand. *Click.* The wheel rolled forward just one notch beneath my fingers. I gasped and snapped my arms tight to my sides, freezing completely stiff. I waited, dreading some loud alarm, but the desk stayed silent. It was just a wheel resting in place.