Working on BST 'each' method.
Complete binary search tree.
Finish basic setups for crypto-square.
Complete crypto-square  plaintext_segments method - use string interpolation!
Finish plaintext segment for crypto.
Almost done with crypto-square - figuring out normalize_ciphertext.
Complete crypto-square. Disagree with second to last test expectation.
Text has 26 characters but uses a square width of 5 - should be 6.
Fix crypto-square test. Add clock exercise.
Small refactor in crypto for readability.