Prime factors

Like many people, I am obsessed with prime numbers. To understand more about them, I plotted a 2D diagram of the natural numbers, showing for each the prime factors and where they occur. I was astonished to find obvious regularities that, in hindsight, make sense, but that I had never encountered before.

Here's the diagram, made manually on a spreadsheet. I'd love to hear your observations.

Here are mine:
* Every number repeats as a factor at its own frequency: 2 repeats at every 2 numbers, 3 at every numbers, etc.
* The numbers where no previous frequency repeats are prime numbers.
* Each number starts its own sequence, displayed here as a line with different slope and color. What is the significance of this slope?
* In this 2D space, one octant is enough to represent all numbers and all factorizations.