It's a really tricky one. If the values move from left-to-right then it gives the illusion that they take time to get from A to B when in fact the value you would be seeing on the left is what has just been output.
We figured by trailing the values from right to left it reflects the fact that the right-most value is what's being output, and everything trailing behind is its tail of history.
So it's a quirk, I suppose!