https://www.codewars.com/kata/57e1e61ba396b3727c000251 - 8-1 https://www.codewars.com/kata/55ecd718f46fba02e5000029 - 8-2 https://www.codewars.com/kata/562f91ff6a8b77dfe900006e - 7-1 https://www.codewars.com/kata/57b06f90e298a7b53d000a86 - 6-1 https://www.codewars.com/kata/5772382d509c65de7e000982 - 5-1 https://replit.com/languages/ruby - ruby online compiler