v                      pos in 0,0, depth in 1,0
>00p10p>#;~:'f-#v_$&00g+00p     v@,a.*g01g00;
                >'d-#v_$&10g+10pv
                     >&10g\-10p v
       ^         ;,a.g01.g00; ~ <  # we do not forget to strip the \n from the input