//  eager confirmation
//  show stack shadow
//  show winding shadow
front
    lfk

flood (p)
    for q in adjacent:

flow (p, cansee)
   // eager confirmation
   for q in adjacent:
      if q not in cansee:
         skip
      
   for q in adjacent:
      if q not in cansee:
         skip
      wantsee = cansee
      wantsee -= confirmed
      cansee &= flood[q]


winding check
    lkf