Jack of Harts

I have seen stonemasons at work, repairing or constructing buildings.  It is very interesting to watch them chiseling away at their stones, perhaps a hundred times on each one.  After the hundred-and-first strike, the stone may be the right size and shape to fit where it needs to be.  Now, I know it was not the last strike that made the stone fit.  It was all the preparation and planning that went into that strike.