The history of the Jack O'Lantern starts at the Irish legend of Stingy Jack who played tricks on and stole from everyone he ever knew including, once, the devil himself. One such story, for there were many different ones, goes that Jack tricked the devil to climb a tree and then surrounded the tree with crosses. The devil, being unable to climb down, struck a deal with Jack. Jack made him promise that he would never enter hell, and the devil agreed. Jack removed the crosses and continued on with his life. When Jack finally died, he was denied entry into heaven because he was too mean to everyone while he was alive. So, down to the gates of hell he was sent, but the devil would not let him enter! Jack didn't know what to do, because he was surrounded by darkness and couldn't find his way around in the land between heaven and hell, so he asked the devil for help. The devil threw him an ember from the fires of hell. Jack took the ember and placed it in a hollowed out turnip and wandered the earth from that time forth carrying his light in a turnip.
This was Tina's first time carving a pumpkin, but she wanted to do something fun (not the common scary face) and ended up deciding on this emoticon: :-P
I looked through a bunch of my photos of Yosemite Valley and drew up a plan in Adobe Illustrator to make a relief, light shaded carving of a slightly exaggerated drawing of the valley. Here's a link to a similar view from Inspiration Point off the yosemite.com website (for those who haven't visited this magnificent park).
Here's a closeup of the landscape in the dark:
Details on how the carving was accomplished can be found in this article.