The key to a strong password is lack of any pattern, meaning, code or anything recognizable, even by a supercomputer. Generating a strong password is a step by step process.

How to Generate a Strong Password - Safeguarding Your Password from Hacker Programs

A strong password is has no recognizable words or proper names in it, English or foreign. Names and words in all languages are in programs available to hackers. With entire dictionaries available on the internet, it is not difficult acquire this data. Even common pet names, like “Spot,” for a dog, are in the vast database of words.

Generating a Strong Password - Numbers Alone are Not Safe

There is no safe harbor in numbers. Hackers also have programs that can run millions of numbers until one makes sense, such as a date. Codes substituting letters for numbers are also easily broken.