# A five-year old explores infinite loops

I’m doing the dishes on a Thursday evening, Griffin is doing his homework. Tabitha is playing quietly with her plastic ponies on the living room floor, talking softly to herself as she likes to do.

She calls me in from the kitchen.

Tabitha: Daddy, why did you tell me skin is made of layers of skin?

Me: Huh?

T: When I was three or four, you told me that skin is made of layers of skin. But then that skin is made of skin, and that’s made of skin… Why did you give me that bad answer?

Me: I don’t remember that, but you have a good point. That was a crummy answer wasn’t it? If skin is made of skin, then what’s that skin made of? Must be skin. And that doesn’t answer your question at all.

Me: I don’t know. But you know what that’s called? That’s an infinite loop. Skin is made of skin, which is made of skin, which is made of skin. It never ends.

[pause]

Me: Did you realize that was a bad answer at the time I gave it, or were you thinking about it now and noticed it?

T: Oh, I was just thinking about that stuff. Like a light bulb in a light bulb in a light bulb.

Me: Huh?

T: Like a light bulb has a light bulb in it, and then a light bulb in that one.

Me: Wait. I don’t get it. Were you thinking about where the light in a light bulb comes from?

T: Yeah.

Me: And light comes from light bulbs, so you thought there must be a light bulb inside the light bulb for the light to come from?

T: Yeah.

Me: Wow. So that’s like my skin answer because each light bulb needs another light bulb inside it to give off light, and that never ends. It’s another infinite loop.

T: Right.