Some will perceive the dancer spinning clockwise, others counterclockwise.
Your perception might even change over time: you might perceive it rotating in the other direction, after a while (closing eyes might help).
What number does it represent?
Well, this is exactly why we need mathematics:
Unambiguous notation, well-defined concepts, clear meaning, no doubts.
Promise not met, I am afraid:
Consider the set of all sets that are not members of themselves. Does this set contain itself?
Very good, then, what is the value of the following sum?
Expanding the sum and using association, we get:
Expanding the sum and using association after the first term, we get:
Let us call: