?? tree rings ... ?? as perhaps helpfully in twilight zone between discrete and continuous ... (also resonating with person growth example .... ??? do humans have any at all detectable seasonal "human rings" in their bones ?? ... ?? hmm, also oak tree elevator idea ??? ..... ??? actual problem of tree growth with (?? for example ...) rings of equal thickness ?? ... ?? issue of perhaps surprisingly robust solution method by dimensional consideration ... ???? ....) ?? maybe similar examples ??? .... ?? ice layers under certain circumstances .... ??? .... mystical relationship between "differential" and "boundary" .... ??? ....

?? "horizontal vs vertical blocks" issue in ftc intuition ... ?? relationship to "cross-dimensional cavalieri principle" ??? .....

?? can tree rings be measured non-invasively nowadays ???