Crafty architects are always trying to cut corners on clients, and architect William C McElroy has done so splendidly with this house. This is among the last examples of a brief San Franciscan vogue for octagonal houses in the 1860s, when some believed that catching direct sunlight from eight angles was healthful. Three afternoons monthly, you can peruse collections of colonial antiques and peek inside a time capsule that McElroy hid under the stairs.