According to Wikipedia, Alexander "Sandy" Calder was born in Lawnton, Pennsylvania, on Jul 22, 1898. His father, Alexander Stirling Calder, was a well-known sculptor who created many public installations, a majority of them in Philadelphia.
The sculptor Alexander Calder is well known for his mobiles. Calder invented the mobile in 1931. Marcel Duchamp suggested the name "mobile". Mobiles are also popular in the nursery, where they hang over cribs to give infants something to entertain them and give them external visual stimulation.