I had three interviews after flying out to Seattle.

1. The first interview was a coding question involving a puzzle. The question was: You have 100 doors in a row, all initially closed. You make 100 passes by the doors, starting with the first door each time. The first time through, you visit every door and toggle it (if closed, you open it; if open, you close it). The second time, you only visit every second door (doors #2, #4, #6). The third time, every third door (doors #3, #6, #9), and so on, until you only visit the 100th door. I was told I could answer using code, so I did so by brute force. I coded it very well, and the interviewer guided me through it.

2. The second interview was a regular Q&A session where I was asked usual questions about problems I'd faced and how I solved them.

3. The third interview was over lunch, and I was asked to test a number of things, such as a PC and a ketchup packet. I didn't do so well in this one.

You have 100 doors in a row that are all initially closed. You make 100 passes by the doors, starting with the first door every time.

The first time through, you visit every door and toggle the door. If the door is closed, you open it; if it's open, you close it.

The second time, you only visit every 2nd door (door #2, #4, #6).

The third time, you visit every 3rd door (door #3, #6, #9), and so on, until you only visit the 100th door.