Window cleaners hanging precariously with squeegees outside office buildings have a new competitor: PPG Industries has introduced a glass with self-cleaning properties. The glass has a transparent, hydrophilic—as well as photocatalytic—coating (on the left in the image above) that spreads out water and prevents beading so as to break down and wash away dirt. The lites come in many sizes, up to 130" by 204". ppg.com