They then followed with You Could Be Born Again, which, despite its title, wasn't an explicitly Christian song. Rather, it continued Chris Dedrick's theme of appreciating (and longing for) childhood. But nothing off the album hit.
1969's Heaven/Earth continued with the semi-spiritual theme, but also featured the surprisingly bitter "2002-A Hit Song" which seemed to be directed at the young audiences who had failed to appreciate the group thus far. (Adult contemporary radio was in its infancy in those days, but it was quick to embrace The Free Design's lush, fluid harmonies and musical craftsmanship. Of course, then as now, grownups didn't buy many records.)
In my opinion, the best of their original albums was 1970's Star/Time/Bubbles/Love, in which the group seemed to embrace its destiny as providers of vocal pop both sophisticated and naive--indeed, the album opens with a song about chewing bubblegum. But, in true Free Design fashion, the music underneath is wonderfully tight. In fact, it flat-out grooves. 1971's The Free Design Sings For Very Important People was a children's album, but still had the group's characteristic sound. The group's supposedly-final album One By One was released in 1972.
I say "supposedly-final" because the group was asked to reunite for one track on the 2000 Brian Wilson tribute CD Caroline Now!--the track "Endless Harmony," which suited them perfectly. Also around this time, many of the original Free Design albums were reissued on CD in Japan, where the group had a considerable following, including Cornelius and Pizzicato Five. Stereolab's Laetitia Sadier also praised the group in many interviews. The times, therefore, seemed right for a new album, and the group released Cosmic Peekaboo in 2001. Its sound was vintage Free Design, though the lyrical focus had shifted more to themes of adulthood. (As I suppose you might expect after thirty years!)
While they've never gotten anything close to the respect they deserve, the Free Design cult is considerable. And with good reason--pick a mildly-popular vocal group from the time, like the Association or the Cowsills, and compare them to The Free Design. The results will be amazingly consistent: anybody with more hits will be weighed in the balance and found wanting. Nobody was ever brave enough to do many of the things which came naturally to The Free Design.