Here is another one from 1880 of Victoria Square. If you find old maps of Adelaide you'd find that Victoria Square was not originally diamond shaped. It was laid out like the other four squares in the city. King William Street went straight through the middle as Grote Street and Wakefield Street met in the middle.
Sara Drake - Illustrated Map of Australia - detail of East Coast including sydney, Melbourne, Adelaide and Brisbane. Made from a mixture of materials, including balsa wood, paper, wire and beads. All the features are handmade. saradrake.com