Step 1: Divide the number into separate digits:
1214 => 1 2 1 4
Step 2: Calculate the distance between each digit and the next (the last digit with the first):
1 to 2 = 1
2 to 1 = 1
1 to 4 = 3
4 to 1 = 3
Step 3: Combine the filters to a string:
1 1 3 3 = 1133