Eternity is a child at play, playing draughts: the kingdom is a child's.
-- Heraclitus, quoted in Hippolytus, Refutation of All Heresies
(trans. Jonathan Barnes, Early Greek Philosophy (2001), pg. 52)
Yesterday I was watching a large group of children at play. About ten or fifteen of them. They were playing tag. As the game progressed they amended the rules as various contingent "facts" arose. Though my thoughts are hardly original, I believe that this is the sort thing that Heraclitus was getting at with regards to the "kingdom" - that is with regard to the nature of human existance and perhaps metaphysics generally.