How then, can Melbourne city extend?

Folding City project proposes an idea to extend the city upward.

The proposal treats the entire city square as a skyscraper, creating a second city directly on top of the existing one. In this skyscraper, the existing city acts as the ground floor and the new city, its basis derived from the original, can be thought of as the second floor, forming such areas as Level 2 Flinders Street on top of Level 1 Flinders Street. The new city above accommodate spaces of similar or related programs to that existing in the same area on the ground floor, connected via vertical transport system- for example, existing general areas of entertainment will expand and connect to additional entertainment venues above, and existing corporate areas will have direct access to more businesses operating above. Furthermore, numerous hidden laneways and alleyways known as Melbourne attraction inspire the formation of additional maze-like folds, much like mezzanines in a building. In this way, the existing city CBD directly influences its own expansion, creating a second city which is very much a part of itself. 

On the upper levels though, these ‘streets’ and ‘laneways’ are not two dimensional walkways, but three dimensional tubular spaces both for occupation and travel. People live and work inside these tubes, as well as walk in it. Travel is also no longer two dimensional, with travelators operating in the X and Y axes and elevators on the Z axis. 

The new part of the city above also distinguishes itself from the existing city through its material quality. The tubular ‘streets’ of the city above is made using transparent and frosted toughened glass, with transparent solar panel films such as those being produced and developed by Sumitomo 3M, introduced at CEATEC Japan 2011. The structure not only allows natural light to permeate through to the ground level, but also contribute to renewable energy production on a city scale. Modes of transport above include elevators and travelators to be run on energy produced through this method, designed to reduce carbon dioxide emission.
The skyscraper city, seemingly floating above in its transparent lightness, explores the opportunities that exist in skyscrapers. Folding the whole city upward exposes much broader surface area for the two cities to interact with, in comparison to the traditional horizontal growth where interaction is limited to its peripheral perimeter. This allows for the city to extend as a unified whole, avoiding isolated situations. Also as a distinctive entity that utilise forefront technology to address environmental issues faced, Folding City project presents an alternative method of urban renewal with a long term perspective.