I clicked OK. I selected Ethernet (my Internet source) from the Share Your Connection From menu, and then checked the AirPort box in the To Computers Using list. I then clicked the checkbox next to Internet Sharing to start up the engine.

With an Android phone that conveniently fell off a truck, I used the Settings app to bring up a list of Wi-Fi networks, selected mine, and tapped away:

redhd

As I watched gears click into place, I knew I had a winner. The phone connected, got an IP address, and started purring along. But I wasn't hearing gears click--no, it was the sound of an instant message alert. I fired up video and saw a smartphone pointed right at my temples.

"So, shamus." It was my crimson colleague. "You figured it out."