Final answer:
The apartment elevator riddle is a logic puzzle that typically illustrates a man's unique circumstance or behavior impacting his use of the elevator, such as being too short to reach the button for his penthouse floor without assistance or an umbrella when it rains.
Step-by-step explanation:
The scenario described of a man who lives in the penthouse of an apartment building taking the elevator down in the morning but only halfway up upon his return unless it's raining is a classic logic puzzle frequently encountered in various forms. The explanation for this occurrence does not relate to physics, but rather to a quirk in the man's behavior or circumstances. However, commonly in these types of puzzles, the man is perhaps too short to reach the button for the penthouse when he enters on the ground floor but can reach it by using an umbrella when it rains or by pressing the buttons with the help of other elevator passengers when returning home. This puzzle is to test lateral thinking rather than academic knowledge.