We came back from the airport with our daughter who has just landed after a four-month trip to India. The car was making a strange beep every so often.
Maybe it is an indicator signal that should have turned off automatically? No, this possibility was quickly eliminated.
Can it be the radio? We made sure the radio was off but the beeps continued.
I looked in the car manual. The only slightly similar symptom described there was a beeping indicating that the air bags are out of order and the air bag light warning signal is also out of order. Was this the reason? In this case there would be a 5-second beep every minute. But our beeps were once every 5 minutes and each beep was for one second. Was there some mistake in the translation of the manual to Hebrew?
I called the garage. Yes, they told me, if I bring the car they can check out what is wrong and fix it. No, they have not encountered this problem before. No, it is not dangerous to drive the car back to Jerusalem. And no, they were not familiar with translation problems in the manual.
Another breakthrough idea! Maybe the beeping came from a mobile phone in the car. Some mobile phones tend to beep when the battery is low or when there is an unread message. We turned off the two mobile phones in the car. This looked promising, but within five minutes another beep came.
When we arrived home I let everybody out and drove to the garage. On the way to the garage I suddenly understood what the source of the beeping was.
Do you?
Combinatorics and more 
Your daughter getting text messages?
It’s clear from the picture; it was your cat. Have you checked your cat’s manual? The Hebrew translation might be misleading, but I think that a one second beep in every five minutes indicates high cholesterol level.
Time to pray?
you didn’t put your seatbelt on?
Your daughters bags were in a seat. They potentially weren’t buckled, or were light enough to indicate a child was sitting in the seat. The weight sensor thus derived the pre-programmed response to warn you of potential catastrophic failure of the airbag.
Answer: There was another mobile phone in the car left there a couple of days earlier that I forgot about.
… under the general title of “Indra’s Pearls,” is worth a detour here, here, here, and here, and there’s even a whole batch of movies here. …www.arsmathematica.net/archives/2008/12/20/the-art-of-mumford/
I am aware that the solution is a bit disappointing; It is a true story so I had to stick to the actual events. Also I thought the actual answer has some educational value, but I don’t remember what it was precisely.
Gil: refresher; P=NP. Proofed.
A good place, Marty, for Malka Heller’s (Yuval Peres’s grandmother) good line: “Why should I be surprised if I can simply disbelieve.”
I recalled one educational point: Even if the coin is under the lamp, you still have to search well.
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