A method for multi-level programming of a phase change memory device includes selecting a word line from multiple word lines and applying multiple bits of data to a bit line of a cell connected to the selected word line. Redirecting the leakage flux limits the cross-talk and associated deleterious effects. The plenum chamber has a shaped exit that causes a predetermined waterfall effect. The substrate is placed on a motor-controlled substrate holding mechanism in a laser removal chamber, and the areas are automatically moved underneath the laser radiation to removal the material. The gel is suitable for use in the mechanical splicing of optical fibers when at least one of the optical fibers is a nano-engineered optical fiber. The shopping cart may remain persistent over multiple sessions of the user.