I thought I'd remembered the code, but when I tried it, it didn't work. I could press the "need assistance" button and endure the ridicule of co-workers I haven't yet met, or I could try to puzzle out the code. I knew that it was a four-digit code that included three numbers. So I set about to go through them methodically.
As I did so, I reflected on the sudoku puzzles that I've played with on and off since erickavan took them up. I don't know that the pattern recognition of those helped, but it felt like the same brain processes were being tapped.