John Thorndyke’s Cases

"We are in luck," Thorndyke remarked, with a glance at the path. "Yesterday's rain has cleared away all old footprints, and prepared the surface for new ones. You see there are three sets of excellent impressions—two leading away from the house, and one set towards it. Now, you notice that both of the sets leading from the house are characterized by deep impressions and short steps, while the set leading to the house has lighter impressions and longer steps. The obvious inference is that he went down the path with a heavy burden, came back emptyhanded, and went down again—and finally—with another heavy burden. You observe, too, that he walked with his stick on each occasion."