Most of us struggle to try to remember how far back our memories can go. Writer Lawn Griffiths surmises it may be about 1949, when he was three years old, on his uncle’s farm, near Polk City, Iowa. That’s where they lived in a simple four-room house: his parents, his two-years-older sister, and his twin brother. A small creek ran just behind the house and the outhouse, and Griffiths rememb . . .