diamond_pattern(n) that returns a list of strings forming a diamond of asterisks: it grows from 1 star up to 2n - 1 stars at the middle row, then shrinks back to 1 star, with each row left-padded with spaces so the diamond is horizontally centered within a field of width 2n - 1.diamond_pattern(2)
[" *", "***", " *"]
Grows from 1 star, peaks at 3 stars (2*2-1), shrinks back to 1, each centered in width 3.
Build the top half with star counts 1, 3, 5, ..., 2n-1, then mirror it (excluding the middle) for the bottom half.
Use `.center(width)` on the star string to handle the padding, or compute spaces manually.