The issue is the "your" imagination part. That is a huge limiting factor. Just because you can create a facsimile of something that functions does not mean you can derive hereto unimagined variations of them. You are assuming that the simulation bends to your will and reshapes itself to make what you want to be a reality, which is not in the prompt. Actually, the prompt quite specifically says that physics and biology remain unchanged by your attempts, so there is no just making shit up, it still has to adhere to the laws of nature and physics. Try to make a dinosaur now and it would suffocate in minutes because the O2 levels now are much lower than when they were alive. Attempt to make a cell phone that exceeds the fundamental quantum limits and it will burn out in an instant, or form a microscale black hole and destroy itself, jury is out on that one.