Olo is a good example. It’s due to a quirk of human perception and the structure of our eyes. They basically designed a machine to try and stimulate the green detecting cones without stimulating the red detecting cones. Normally if something pure green hits your eyes, it stimulates those red cones too. So this is something our bodies are capable of perceiving but not something that we can ever perceive under normal circumstances.

Is it a “new color”? Not exactly. Did it take a good bit of imagination to conceive trying to get our brains to see it? Yes.

Just imagine them invariant to any 3D rotation.

Now write a proof showing that your set is neither countably nor uncountably infinite and become the most famous mathematician I’ve replied to on Lemmy today

You can project a 4D object onto a 3D space just like you can project a 3D object onto a 2D plane. If you use stereoscopic trickery you can for example watch a tesseract rotate on a phone screen. Don’t ask me how I know but if you spend an evening doing that sorta thing on shrooms 4D geometry might start feeling intuitive to you. Your physical senses are limited to three dimensions, your mind genuinely isn’t.