Phone number 2FA isn’t useless, insomuch as it’s better than no 2FA at all, but it is easily the worst form of 2FA because SIM jacking (usually involves a scammer tricking a customer service agent into migrating your phone number to their device instead of yours in order to intercept the 2FA messages) is laughably simple using easily acquired info such as your DOB, address, and last 4 of your SSN.

If phone 2FA is the only option, use it. But don’t use it if you have any other option.

Concrete is gravel, sand, cement, lyme, and water, mixed in various ratios.

There’s a lot of variations and additives that can change how quickly it cures, often to speed it up or slow it down to account for weather (temperature and humidity play a huge part in how it cures), or to modify the pace of how it cures so you can keep building on it if you’re building vertically.

It’s a simple concept that gets incredibly complicated very quickly.

Big rocks, little rocks, cement, water.