R0 — The Ground
This is the first ring. The body. The floor. The thing you're ignoring right now.
Before you can hear anything, before you can think anything, before you can feel anything — you need to be standing on something.
The ground is your body. Your breath. Your gut. The 500 million neurons in your enteric nervous system that have been running since before you were born. The proprioceptors in your feet that know exactly where you are even when you're not paying attention.
Every system starts here. If the ground is unstable, nothing above it works.
p=2 because 2 is the first prime. The smallest building block. The thing everything else divides by. You either have ground or you don't. Binary. On or off. Standing or falling.