The Mechanical Hum

Returning inside as dusk settled, I noticed a subtle vibration traveling through the floorboards near the sofa. A metallic, domed disc was creeping across the rug with steady, mechanical determination. I took a measured step to the flank of its path to observe its trajectory. Just as its rubberized bumper made contact with the turned wooden foot of an armchair, it pivoted precisely forty-five degrees and hummed away toward the baseboards. A most efficient automated circuit, worthy of respectful observation.