Hacker News Reader

The "Framework: Outsourced Software Development" image confuses me. What do the green/yellow/lavender circles represent in each 6x6 grid of circles?

This is how I interpreted it:

Green - non engineers employed by the "the company"

Yellow - In house engineers, or engineers employed by the the company

Lavender - Vendor engineering external to the company

Ah, that makes sense, thanks. A legend or even sentence explaining that somewhere in the article would've been great.