There's no obvious, singular definition of "is" for something like that tower. You have to describe it via a generating process or an equation. If you ask for t

There's no obvious, singular definition of "is" for something like that tower. You have to describe it via a generating process or an equation. If you ask for the values "x" such that "x = sqrt(2)^x" then you need to consider the chance there are multiple such "x"es. If you consider it the limit result of continually applying f(x) = sqrt(2)^x then you'll get the least fixed point.