Stairway to Escher

BallFiend did a drawing today... whipped it up in a minute or two, while he was waiting for a ride on the kiddie-train at Santaland in a Melbourne department store. At the time, I didn't even look at it, just grabbed it and shoved it in the bag as we hurried off when his turn came up.

It wasn't until we were back at home and he explained it to me that I realised it was pretty clever for a 5 year old...

"It's a staircase. And you can turn it this way [he rotates the paper 180 degrees] and it's the same staircase." he explained.

I showed DeepSpice when he got home from work, who promptly recognised it as rotational symmetry.

It's looking like BallFiend is going to have greater mathematical aptitude than his mother!
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