Pause at first, then roll and dip and waft off. Then waft in, and dip and finish with a pause. Keep the arm moving while painting. For the rock itself paint the outline, pausing at the beginning and end. Notice these two ends are in a straight line.
Veins run parallel to the outside line, criss-crossing backward.
Note that the front line comes forward, and ends up below the outline. For a wash, which is only ever added when the whole painting is finished, use the soft white brush. Rinse it, take out some of the water and tip in grey.