[contravariant]

> Does this mean that the second block from a random point in time is, on average, 20 minutes away?

No, under the assumptions in this article the next block is on average 10 minutes away.

The paradox is that at any random point in time the previous block will also have been, on average, 10 minutes ago. Meaning that if you pick a random point in time and wait for the next block then on average you'll wait for 10 minutes, but the block will have taken 20 minutes in total to mine. Despite the fact that blocks are only supposed to take 10 minutes on average.