What interesting methods or methods of authorization on the site do you know?

Question

User identification

Greetings
I thought about authorization on the site, some unusual and at the same time reliable and interesting. Somewhere I once saw an authorization method by the type of random generation of a 5x5 table in which numbers appear randomly, on a certain combination of which you need to hover over and click on them, but that site has already been lost.
Do you know similar and/or unusual authorization methods? If there are links to ready-made examples and a library, it will be great.

Answer 1

Authorization should not be interesting , but convenient and fast .
Add the ability to log in to your resource through accounts of other services (the same social networks). This will be enough.
Ps (reply to the topic): you can put something like electronic signatures instead of passwords =)

Answer 2

I saw authorization using the position of the cursor in the picture (given coordinate during registration), then in the modal window it is proposed to enter a password.

Answer 3

HERE click on the Search button and you will see.