to modify an existing program and to understand how iterative refinement and the design recipe help with this task
Exercises
Exercise 10.1. Modify the StarMoney game so that all game thalers are in the air at any point during the game.
Modify the StarMoney game so that many but not all game thalers are in the air at any point during the game. Add thalers as they land and/or are caught.
Exercise 10.2. Modify the function that moves the girl so that it can fly in response to all four arrows (↑, ↓, ←, →).
Exercise 10.3. Implement some other game.