Until now, a bar code had to be visible to be scanned. But that's not the case any more thanks to research at NASA's Marshall Space Flight Center in Huntsville, Ala. Now, symbols covered with as many as six layers of paint can be found and read using a specially developed handheld magnetic device. It reads symbols that have been originally applied using paint, ink and pastes with magnetic properties. Initial work is limited to the two-dimensional Data Matrix symbol developed by Robotic Vision Systems, which will sell the scanner through a license with NASA. Expected users range from the Department of Defense to the electronics and pharmaceuticals industries.