If Charlie thought it was a logic puzzle that probably meant the gate wasn't labeled “push” or “pull” and he hadn't thought to try both. But, much as he hated to admit it, Lee had nothing better to do on a Saturday. He didn't think Charlie would keep his promise to not walk in on him in the shower, but if there was a logic puzzle at least that would provide some diversion. He reluctantly agreed.
'Old Man Morris' was a professor emeritus who rarely left his large house in the forest that abutted the college. And he wasn't very welcoming of visitors, as evidenced by the large stone wall around the property, broken only by the iron gate Lee and Charlie were approaching. It was probably Morris's reclusive and mysterious nature, ironically, that brought him so much attention from the students.
“I hear he's a wizard.” said Charlie. Right, thought Lee, that might be a factor too.
“He's not a wizard. He's a scientist. And I'm sure his work is insufficiently advanced to be indistinguishable from magic.” Charlie wouldn't get the reference, but Lee made it anyway. Morris had been in the psychology department, but he studied the psychology of decision-making and game theory, so he had also taught some courses in economics and math. His particular research area was games (broadly defined) of perfect information but of some complexity. Essentially, he was trying to show why all of the assumptions of economics were wrong (it's common knowledge that they are, but he was trying to show why). Lee had skimmed some of his work, and thought it would be neat to meet him.
“See, there's the lock.” They'd reached the gate, and Charlie indicated an elongated pyramid with a loop on the end holding the gate shut. The sides were blank, but when Lee pulled it up he saw that the bottom had three circular holes. Two of them ran up to near the tip of the pyramid, but the third should perhaps not be described as a hole at all, since it was filled in with a bronze disc. “Well, can you solve it?”
“Give me some time to look at it, will you?” Lee tried pushing the bronze disc inward, but it wouldn't give. He didn't notice that it seemed to have some lateral give, so he tried sliding it towards one of the other holes, and sure enough it slid under the steel between them and filled up the other hole. Below it was revealed another bronze disc, this one smaller as the hole tapered. Lee tried sliding it over like he had the first, but it wouldn't go. However, he found that it would slide over to the third hole, but it just revealed yet another disc below it.
It didn't take Lee long to recognize a Towers of Hanoi puzzle. The only difficulty was that you couldn't see how many discs there were in total, so you didn't know how long it would take or how to start. Actually, Lee reflected, it didn't matter how he started, because he couldn't distinguish the two other holes and so assumed that moving all the discs into either of them would suffice. “Yeah, I can solve it, but it will take me, oh, five minutes.” The estimate was essentially a lie – Lee knew that the time to solve Towers of Hanoi was exponential in the number of discs, and since he didn't know the number of discs he could easily be off by a factor of four in either direction. But he didn't want to try explaining that to Charlie.
As Lee was working through the relatively mindless recursive algorithm to solve the puzzle, he reflected on Morris's choice of lock. First, it took a long time to open, even if you knew how. Morris really didn't get out much or receive many visitors. Second, and more interestingly, it wasn't a very good lock. Towers of Hanoi isn't exactly an obscure logic puzzle – anyone with much exposure to logic at all would be able to solve it. Maybe Morris didn't want to discourage visitors as much as it seemed, but just wanted to select a certain type of visitor?
Lee was pleased to find that there were only six discs, and so it was little more than a minute later when he slid the largest disc in place over the others and the loop popped open with a click from some unseen mechanism. “It's open,” he called to Charlie, who was leaning against a tree and either admiring his abs or picking out bellybutton lint – Lee couldn't tell which, or both – as he waited.
“Finally.” You're welcome, thought Lee. “Alright, you can go.”
Lee shrugged and turned around and began walking back to campus, listening as Charlie opened the gate and went inside. Lee had wanted to meet Morris, but he learned long ago that it was easier not to confront Charlie – it was easier to deceive him. He slipped behind a tree to wait until Charlie was out of sight.
After a minute or two he judged that he had waited long enough, and walked back to the gate. Charlie had left it open, in his usual slovenly fashion, which saved Lee the trouble of opening it again. He slipped through the gate. As he was about to click the lock shut, he considered that he might want to make a hasty egress – if Morris had a guard dog, for instance – and it would behoove him to leave the gate open. So he did.
Beyond the gate, the tree-lined drive turned sharply to the right. Lee followed it to find that not long after the right turn it veered sharply leftward. As he rounded that second curve, he was surprised to get a clear view of the house. He ducked behind a tree and cautiously peered out, looking for Charlie. He didn't see him, and so guardedly approached the house.
It was nothing to speak of – average size, drab off-white color, porch out front. Lee climbed the stairs to the porch, and was amused to see a “Welcome” mat in front of the door. Nothing else about Morris had been particularly welcoming. He was wiping his feet on it as he rang the doorbell, and then it swung out from under him. Lee had fallen – literally – into Morris's trap.