We show that a class of extremal four-dimensional supersymmetric "highbranes", i.e. string and domain wall solutions, can be interpreted as intersections of four ten-dimensional Dirichlet branes. These d = 4 solutions are related, via T -duality in ten dimensions, to the four-dimensional extremal Maxwell/scalar black holes that are characterized by a scalar coupling parameter a with a = 0, 1/ √ 3, 1, √ 3.