I heard of an old Zen exercise. Two low tables a few yards apart. On one table a large rounded stone – a big pebble – heavy but manageable. The monk approaches the stone, bends his legs and embraces it. He then lifts it up by straightening his legs and takes it to the other table where he carefully and gently deposits it by bending his legs. He then straightens up, places his hands together in an attitude of reverent prayer and utters a mantram or invocation. After a second or two he repeats. This goes on for an hour or so. The idea, as with all repetitive simple exercises, is that the mind eventually becomes quiet and the monk becomes possessed by the doing. So much so that the pebble enters his dantien – the stone in the belly – a mood of detached sober involvement, but also an energetic actuality.