Wallace is getting so interested in the world around him — grabbing and rolling around. He seems to recognize his favorite songs and rhymes: “Trot, Trot to Boston,” peek-a-boo, “Ride a Cock Horse to Banbury Cross,” “One, Two, Buckle My Shoe” . . . And his whole face lights up when he sees someone he loves — especially his sisters. The girls have sung dozens of rounds of “The Ants Go Marching” to keep him happy in the car over the past few weeks. We love our tiny, irresistible, 4-month-old boy so much.