Anyway. Break your problem down into smaller parts.
I’m serious!
If you try to do the whole thing at once it will be a mess.
Start with the big problem:
“write a program that randomly presents a shape out of a collection of 3 (let’s say line out of rectangle,ellipse and line) and when users press a key it will change to another shape in a fixed order”
To me, this breaks down into the following:
- Write a program.
- Do something randomly.
- Present a shape (out of three possible shapes).
- Detect user input (key presses).
- Change to another shape.
- Make sure the shapes appear in a fixed order.