A method and system are disclosed for creating dynamic models of etch processes in semiconductor manufacturing. The information may include any or all of how long an author has been active in the group, in what other newsgroups the author participates, to what other threads of conversation the author contributes, and which other participants the author most often engages in discussion. The plurality of red LEDs utilize at least one current regulator to maintain a constant level of illumination. The position of the light source is tracked from frame to frame and the position information is output for use by application software or circuitry to direct movement of a pointer in a computer display, for example. The blowing agent is preferably a compound that releases gas bubbles upon acidification, such as NaHCO3. and preferably no more than 250 C.