 What was thought to be used as an indication to settle the confusion between the crew and the two humans in moon-town?
Not only would there be life traces on that little moon, but it would be a lively place. Naturally they did not get results at once, nor did they expect to; it required a fine adjustment. But they were disappointed that they found nothing for several hours as they hovered high over the rotation. As though there were but one city, if that is its form. But this might be so varied or so unfamiliar that often both the machine and the designer of it were puzzled as to how to read the results. It was for this reason that Glaser used that model no more, but built others more amenable. And it was for this reason also that the owners of Little Probe had acquired the original machine so cheaply. On Earth it had read Positive on a number of crack-pots, including Waxey Sax, a jazz tootler who could not even read music. In space it had been a sound guide to the unusual intelligences encountered. He then narrowed to a smaller area (apparently one individual, though this could not be certain) and got very definite action. So among the intelligences there was at least one that might be extraordinary, though possibly in a crackpot way. Dawn did not come to the moon-town. The Little Probe hovered stationary in the light and the moon-town came up under the dawn. "Not a building, not two sticks or stones placed together. And those two ... why, they could well be Earth-people.
 A game of checkers
 An inquisition about knowledge  A game of checkers  A contest of preternatural intellect  A physical test