Part of this puzzle is to discover the specs from the screenshot. Nice try though with your 1x1 squares. It's witty at best, but unfortunately for you, not compliant with the intended solution. I suggest you apply for a job at G00gle, they love out-of-the-box thinkers like yourself. Who knows, your 1x1 squares might fit their true rectangles ..

@g964 could you take a look at the suggestion up there and apply it if it's fine?

I'm not against your idea of adding "the fewest necessary", but that's the author's choice. It's his/her kata after all. I don't think it spoils anything and makes the requirements clearer. IMHO a solution with squares of size 1 is not clever, it's trivial.

Do you really think that answering with a list of ones is a valid answer? Isn't that too simple for a 6kyu kata? I'm not being snarky nor condescendent. Just putting the problem in context. Wait for the kata's author to answer you if you want a better explanation. Note the PUZZLES tag at the end, figuring out how to properly cut it could be part of the task.

From the kata's description:

Can you translate this drawing into an algorithm?

Did you see the drawing? Has it 15 1x1 squares?

No, your solution is not valid. I'm not sure if the instructions are like that so you reverse engineer your answer seeing the examples or not.