We explore maximally supersymmetric Yang-Mills theory with walls of impurities respecting half of its supersymmetry. The walls carry fundamental or bifundamental matter multiplets. We employ three-dimensional N=2 superspace language to identify the Higgs branch of this theory. We find that the vacuum conditions determining the Higgs branch are exactly the bow equations determining Yang-Mills instantons on a multi Taub-NUT space. Under the electric-magnetic duality, the fundamental- and bifundamental-carrying impurity walls are interchanged, while the super Yang-Mills theory describing the bulk is mapped to itself. We perform a one-loop computation on the Coulomb branch of the dual theory to find the asymptotic metric on the original Higgs branch.