  We begin by reviewing the noncommutative supersymmetric tubular
configurations in the matrix theory. We identify the worldvolume gauge fields,
the charges and the moment of R-R charges carried by the tube. We also study
the fluctuations around many tubes and tube-D0 systems. Based on the
supersymmetric tubes, we have constructed more general configurations that
approach supersymmetric tubes asymptotically. These include a bend with angle
and a junction that connects two tubes to one. The junction may be interpreted
as a finite-energy domain wall that interpolates U(1) and U(2) worldvolume
gauge theories. We also construct a tube along which the noncommutativity scale
changes. Relying upon these basic units of operations, one may build physical
configurations corresponding to any shape of Riemann surfaces of arbitrary
topology. Variations of the noncommutativity scale are allowed over the Riemann
surfaces. Particularly simple such configurations are Y-shaped junctions.
