Using the outer buttons you can scroll through the following "screens": "HH:MM", "MM:ss", "dd.mm.", "YYYY" and finally one screen with all LEDs turned off.
Using the inner two buttons you can select either the left or the right digit group. Then you can use the outer buttons to increment/decrement the digit group which is then highlighted using the decimal dots.
I was lazy and used 30 days for incrementing the month value which makes setting the date kinda awkward.
Also the buttons use the internal pull up resistors of the arduino.
Want to add a screen displaying swatch beats and another displaying the time in hexadecimal format by dividing the day in 16 hexhours which are equivalent to 1,5 hours, and these into 16 hexminutes which are equivalent to 5,625 minutes, etc.