Square
When presented with a figure of four equal straight sides and four right angles in a white abyss, it seems to be just a square. When you tilt your head, it becomes a diamond. Then you walk to the edge of the diamond to see it extrudes far back: for miles, actually. So, you take several hundred steps back and lay on your side. The ground materializes under your feet and the wall underneath your side disappears. Gravity shifts your weight back to the bottom of your feet and you stare at the skyscraper, now right-side up. You hear screams on the other side of the structure and walk a short distance to see another human, staring at the same structure; terrified. What is that person seeing? In what direction did they tilt their head to that it displayed something so terrifying? You and that person clearly don't see the same thing. You look back at the structure. It's just a skyscraper, isn't it?
Now exit out of your abyss, back to reality. Look at what the person next to you is looking at. Are you seeing the same thing as them? Yes? Or do you just think you are? Our senses are subjective, and your reality is just a tangible manipulation of that white abyss. Society’s rules are just vague enough to consider some of your subjective senses as objective. Are you sure you exited out? Touch your phone screen and realize it's smooth. But what is the definition of ‘smooth’ to the person next to you? The two of you consider that phone screen similarly enough to recognize that it's smooth, but you cannot truly experience what that person is feeling. It could be completely different. If every decision you make is a resulted calculation of all of your previous experiences compiled together, then doesn't that explain the concept of ‘disagreement’? Every choice you make is the beginning of a disagreement, because the reasoning behind your choice will never be identical to another who makes a different choice: or even the same one. Next time, tilt your head.