Don't worry: squares will still be squares, circles will still be circles, and reality for all intents and purposes will remain pretty similar. There might be some "enhancements" to your perception including increased pattern detection, and notice how vibrant and detailed reality can actually be. The way psychedelics alter your perception of consensual reality after they've long worn off, is most notable in the increased pattern perception. I'm convinced that these patterns that crop up everywhere from the dirt to water droplets to paint on the wall to cement on the floor, or cells in your skin or whatever...that are all pretty similar - all of these patterns have always existed, but psychedelics train the eye to see order and logic where only haphazardness, chaos and randomness were detected before. Aside of just patterns, psychedelics can call your attention to details in reality that you may typically overlook. Psychedelics have a way of showing you things "under the microscope" so that when you're back to baseline, you've learned things about the world around you that you typically would have normally just filtered out. So many details get filtered out from our awareness in order to allow us to remain focused on something, and to avoid going crazy.