I was trying to explain the concept of the function
that takes an array
arr and reduces it pairwise using the binary operator
op until just one number is left.
For example, the
sum() function can then be written
sum(arr) = reduce(+, arr)
To explain what
reduce() does, I thought it would be nice to have a great
graph, but I couldn't find one online.
Thus, I attempted to make one myself using TikZ. I failed: