SSRuby Katas 8.1 https://www.codewars.com/kata/my-head-is-at-the-wrong-end 8.2 https://www.codewars.com/kata/to-square-root-or-not-to-square-root 7.1 https://www.codewars.com/kata/recursive-replication 6.1 https://www.codewars.com/kata/build-a-pile-of-cubes 5.1 https://www.codewars.com/kata/which-x-for-that-sum