If you search for the phrase "丈二和尚摸不着头脑" in Pleco (iOS), one of the definitions (from 'CC') is 'like a three-meter high monk, you can't rub his head'. If we take the modern meaning of 丈 as being 'equal to 10 chi [尺]', or 3.33 metres, then in this phrase the monk seems to in fact be over six...