Step 1: Divide the number into separate digits:
8772 => 8 7 7 2
Step 2: Calculate the distance between each digit and the next (the last digit with the first):
8 to 7 = 1
7 to 7 = 0
7 to 2 = 5
2 to 8 = 6
Step 3: Combine the filters to a string:
1 0 5 6 = 1056