Therefore the sentence-makers have thus expressed themselves:-- 'The Tao, when brightest seen, seems light to lack; Who progress in it makes, seems drawing back; Its even way is like a rugged track. Its highest virtue from the vale doth rise; Its greatest beauty seems to offend the eyes; And he has most whose lot the least supplies. Its firmest virtue seems but poor and low; Its solid truth seems change to undergo; Its largest square doth yet no corner show A vessel great, it is the slowest made; Loud is its sound, but never word it said; A semblance great, the shadow of a shade.'