Step 1: Divide the number into separate digits:
4742 => 4 7 4 2
Step 2: Calculate the distance between each digit and the next (the last digit with the first):
4 to 7 = 3
7 to 4 = 3
4 to 2 = 2
2 to 4 = 2
Step 3: Combine the filters to a string:
3 3 2 2 = 3322