SANTA MONICA, CA. : Lucinda, 5, demonstrates her musical skills in the upstairs common area, which houses many of the children's toys. Architects Erla Dogg Ingjaldsdottir and Tryggvi Thornsteinsson, who work under the firm name Minarc, converted a 1970s apartment building into a family house for Rachel Klauber-Speiden, Josh Empson and their two children, Lucinda, 5, and Becket, 3.