'Pat' is onomatopoeic in origin, and what happens after the 'Pat' is always the separation of the 'Bit' which does the 'Patting' and the 'Bit' which was 'Patted'. The 'Bits' are now said to be 'Apart', each one is 'A Part' and what they just did together was 'To Part' or they did 'Do Part'.
'Body' is most interesting when we look at the South American approach. Their word for the food you don't eat, 'Tee' (i.e. your body) is the reverse homophone of the word for consuming food (Eat). Similar lines of enquiry lead us to '*Ed' for the *PIE 'eat' and 'De' for the Germanic 'You' (also Die/Doo meaning 'two' comes from this).
Ages of literacy completely kill off the practice of creating words via reverse homophony, although certain tell-tale signs nicely illustrate their shadowy existences.
Nice sign, on no knife fine, enough funny, phoney yknow'th. See is.