Many artists have a muse, something that is a huge source of creative inspiration for them. Peg Sandin is an artist based in Ironwood, MI, and her muse is Lake Superior. WXPR's Larry Lapachin has the story. Lake Superior welcomes many visitors to its shores. Some are captivated by the unpredictable vastness of water that stretches to the horizon, while others are enamored with its soaring cliffs and spectacular waterfalls. Still others find solitude in sifting through rocks along the beach,