0 convert to zero
TPP: there are two transformations in this TDD cycle. The first one is {} -> nil, which makes the code compile and fail the test. The second one is nil -> constant, which makes the code pass the test.
1 convert to one
TPP: unconditional -> if
2 convert to 2, and then single digit convert to one word
TPP: scala -> array
number convert to one word
TPP: statement -> statements. Adding a constant element to array is treated as a statement.