I finaly got a chance to do this challenge after getting some more rocks the other day.
I enjoyed doing it, but learnt that I aint as fast as I thought I could be and didn't get the notches deep as I wanted them and I didn't get to touch up the edges with pressure either. I set a timer for fifteen minutes and would stop to take pictures each time the timer ran out then I would do the next fifteen minutes, so all together with pics this is a little over an hours worth of work.
Here's the rock