What are the three categories of engineering models?

Captain Kaleem on Instagram: "3 Skills that just need 3 months Skills are not that should kept as secret they have to be expressed - Odd statement, but it’s true. I am in my own space where I can create or do whatever I want, but it is the same thing that everyone can know. Just give yourself a 90 days. Don’t take it as a challenge. Take it as lifestyle that you are going to follow your lifetime. It should not be more tough, and it should not be more easy. Should be something that you enjoy. Enj