Step 1: Divide the number into separate digits:
5059 => 5 0 5 9
Step 2: Calculate the distance between each digit and the next (the last digit with the first):
5 to 0 = 5
0 to 5 = 5
5 to 9 = 4
9 to 5 = 4
Step 3: Combine the filters to a string:
5 5 4 4 = 5544