Binary
The Campanile (also known as the Sather Tower) in Berkeley has a clock on each of its four vertical faces. The clocks usually do not match, and they didn't today, when I was almost late for an appointment. I'd forgotten my watch at home, and, after glancing at the tower, asked a random passerby, "Is it two or two-fifteen right now?"
"Yes," he replied mysteriously.
Trying to outwit him, I asked again, "Is it two xor two-fifteen?"
"Of course not," he replied indignantly.
"All right, then, do you know the time?"
"Huh-uh," he shook his head. "But I do know that it's either two, or two-fifteen--look at the clock tower!"
"Yes," he replied mysteriously.
Trying to outwit him, I asked again, "Is it two xor two-fifteen?"
"Of course not," he replied indignantly.
"All right, then, do you know the time?"
"Huh-uh," he shook his head. "But I do know that it's either two, or two-fifteen--look at the clock tower!"