Everything about the USB interface!

Hello everyone, Ebyte here.
As a necessary interface for computers, USB can be regarded as a universal interface.Just a quick question, how do you differentiate between USB2.0 and USB3.0? Judging by color? Or jusding from the number of pins?
In fact, you can differentiate it by the logo next to the USB interface.
If it is with a SS mark, USB3.0 interface it is. SS—Super Speed. And the lightning mark means it supports shutdown charging and fast charging. But why do the USB ports look different?