My husband was digging under yet another enormous tree stump and cutting roots. I was pulling out the roots as he cut them. One smallish root seemed to be unusually heavy and was very difficult to pull, even with both of us pulling together.
A bit more digging and we found out why. Somehow as this root had grown, it had tunneled right through a very solid rock.
What great visual proof that with time and perseverance, nothing is impossible!