This display - the Information Percolator - is formed using air bubbles rising up tubes of water. By properly controlling the release of air, a set of pixels which scroll up the display is created. This allows a rendition of any (small, black and white) image to be displayed.
The Information Percolator is a research project sponsored by the Human Computer Interaction Institute at Carnegie Mellon University. It was created by Jeremy M. Heiner, Scott E. Hudson, and Kenichiro Tanaka.
For more information about the Bubble Wall, please visit http://www-2.cs.cmu.edu/~hudson/bubbles/