In Palo Alto, one architect has a novel plan to help multigenerational households. Accessory dwelling units have become popular as new state laws have made it easier to get permits for ADU's.

For his own 2,100-square-foot home in a double-lot compound in Palo Alto, Bellomo has built a house of concrete tucked in close to a 30-foot gnarled oak tree, a Palo Alto landmark.