The process that Helena is using can be described as "iterative development" or "incremental development." In this approach, a developer starts with a general idea or pseudocode and progressively adds more details, refines the code, and may make changes based on testing or feedback. This cycle of writing, testing, and refining helps in gradually shaping the final program.
Additionally, the term "prototyping" might also apply, as she is creating an initial version and then modifying it based on her thoughts and the requirements of the program.