Step 1: Divide the number into separate digits:
6768 => 6 7 6 8
Step 2: Calculate the distance between each digit and the next (the last digit with the first):
6 to 7 = 1
7 to 6 = 1
6 to 8 = 2
8 to 6 = 2
Step 3: Combine the filters to a string:
1 1 2 2 = 1122