Step 1: Divide the number into separate digits:
4162 => 4 1 6 2
Step 2: Calculate the distance between each digit and the next (the last digit with the first):
4 to 1 = 3
1 to 6 = 5
6 to 2 = 4
2 to 4 = 2
Step 3: Combine the filters to a string:
3 5 4 2 = 3542