Simulations are a difficult concept to comprehend and limit. On the one hand, a simulation can create an image that so closely resembles it's original/referrent, it makes the referrent inconsequential, and impacts the viewer in the same way as the original would have. One the other hand, there are levels at which one must recognize the difference of the simulation as not just a simulation, but a new entity all its own.
For example, virtual reality must be understood not only as an attempt to recreate the reality we all commonly know, but also to create a new world altogether that has a new set of possibilities and responsibilities. The Street in Snow Crash isn't just recreating a true worldly street, but an environment that retains many of the salient characteristics of a street while revolutionizing ideas of identity and human interaction. Though the users still retain a need for metaphor to a true worldly street, this isn't the only model for traversing a VR space, and though the avatars on the Street often resemble the people that are controlling them, that are them, they can also take the form of an eagle, or a giant penis. Though this sort of image is jarring, and does break a metaphor/sign between the virtual reality and the physical reality, the Streets inhabitants can quickly adjust to this world and relinquish their expectations for limits which the physical world has. According to Marcos Novak, cyberspace if the place of magic, allowing us to realize our imaginations.