dbug: no such thing as fallback duct
++ bone-to-pairs
|= [=bone ossuary]
^- (list [@t json])
- =/ fallback-duct=duct
- :: if backward flow, fall back to "original" duct
- ::
- ?: =(0 (mod bone 2)) ~
- (~(gut by by-bone) (dec bone) ~)
:~ 'bone'^(numb bone)
- 'duct'^(from-duct (~(gut by by-bone) bone fallback-duct))
+ 'duct'^(from-duct (~(gut by by-bone) bone ~))
==
::
++ maybe
