I love it when players innovate by themselves.
Last night - while the 2nd XI put a strong GHK side to bed in the T20 - a handful of bowlers decided to practice their yorkers. The problem was that we only had a few yards to practice in and no pitch.
So, we found an old crate that was put on a yorker length, set up the stumps (and a marker cone for a good length for variation) and tried to bowl the ball under the crate for instant feedback on hitting the length. Boom!
This was entirely self-directed. Brilliant lads, brilliant.