IMITATION GAME — Several days ago Peggy and I were playing a familiar game as she sat in her high chair. Peggy would beat on the tray with the flat of her palm somewhere between two and seven times, then wait for me to repeat what she had done. She varied the number of whacks each time. Finally, she turned her head sideways, palm vertical and thumb down, and gently beat a few times on the tray with the tip of her thumb. Then she looked expectantly at me, and laughed with delight when I imitated her action.