Can't see the movie? Download Quicktime
Player (it's free) for Macintosh or Windows at
http://www.apple.com/quicktime/
OR look at images of the construction here.
Day 3
Drag your mouse left and right and up and down around the
picture to see the construction. Use the shift key to zoom in and control
to zoom out. You may also use the controls at the bottom of the picture.