Okay, I managed to find an image on the net that shows the pyramid of Kukulkan, but I'm having difficulty in seeing where exactly this act of shadow and light takes place. Help?! :o)

http://www.tropicalevergreens.com/equinox.html

I think I'm looking in the shadow when I should be looking in the light, but I'm not sure. LOL

On a side note, I found some rather nice images of the pyramid which also show the steps...whewee!

http://www.locogringo.com/past_spotlights/apr2002/chichen.html