A man is told to make a circle
He makes this:
Where is the man?
In Manhattan, because that is what a "circle" (defined to be the set of points of a certain set distance d away from a given point) looks like when using the taxicab (or Manhattan) metric.
He has made a rapid escape from the scene because he actually didn't know what a "circle" was.
No wait.
He makes it.
Well, he draws a circle. And then he makes the diamond...
So where is the man?
Think what I have just done.
I am that man.
Clearly the man is
in $L^1$ space.
He was asked to draw a circle, namely the set of all points at distance $1$ from a fixed centre.
We imagine this as looking round, because we live in Euclidean $L^2$ space. But this man lives in $L^1$ space, in which the unit circle is a square box because the concept of 'distance' is defined differently. More generally, unit circles in $L^p$ space look like this for assorted values of $p$:
He's in another distance metric, one where distance is determined by the addition of coordinates, instead of pythagorean theorem.