There are three stages in the development of the Harry Seidler offices and top floor apartments. The first building (No. 2 Glen St) was completed in 1973. It is an 11m clear span office building of prestressed expressively profiled T-beams and vertical exterior concrete sunblades.

The first addition of 1988 (No. 2A Glen St) extends the offices on lower floors and adds a penthouse apartment on top. Entry is into a two storey high space with a presentation theatre and facilities for entertaining.

The half-elliptical Indian granite dining table allows guests to sit against the curved side so that they can see the splendid water view; the hosts sit on the opposite side and face their guests.

A curved stair leads to the upper floor lounge, study and master bedroom suite.

Within the straight outline plan, flowing curves enrich the spatially open interior. Only the artworks (by Albers, Stella, Lichtenstein and Noland) are colourful in contrast to the neutral grey, white and black interior.

The second addition of 1994 (No. 4 Glen St) adds more offices below and a roof terrace shared with another apartment.