[W/K] :: on all fours

  All fours \All` fours"\ [formerly, All` four".]
     All four legs of a quadruped; or the two legs and two arms of
     a person.
     [1913 Webster]
  
     To be, go, or run, on all fours (Fig.), to be on the
        same footing; to correspond (with) exactly; to be alike in
        all the circumstances to be considered. "This example is
        on all fours with the other." "No simile can go on all
        fours." --Macaulay.
        [1913 Webster]

  on all fours
       adv : on hands and knees; "he got down on all fours to play with
             his grandson"