…and you'll enjoy exploring Dave Bollinger's photostream further, a bold and wonder-full use of Flickr

"…A typical use might be to determine when the sun will set along the axis of a mountain valley, or when a full moon rise will rise across a lake. The application uses Google Maps providing users the ability to select a location and determine the time and azimuth of sunrise or sunset for a given date or dates."

PowerPoint presentation, bulleted and factiferous but authoritative

a nice summary of Leonardo's "intellectual phases" via Bruce Sterling's Beyond The Beyond