This pin is unlocked by logging in on various days in a row.  An interruption of the login days has the consequence that you have to start from the beginning.

This is the amount you need:

Level	Quantity
	2 days
	7 days
	14 days
	21 days
	30 days

After reaching the 5th level, you can level this pin again with the same number. After that, the color no longer changes, but a number appears on the pin. This shows other users how many times you have reached the last level.