Kata

Jamie is a programmer, and James' girlfriend. She likes diamonds, and wants a diamond string from James. Since James doesn't know how to make this happen, he needs your help.

Task

You need to return a string that looks like a diamond shape when printed on the screen, using asterisk (*) characters. Trailing spaces should be removed, and every line must be terminated with a newline character (\n).

Return null/nil/None/... if the input is an even number or negative, as it is not possible to print a diamond of even or negative size.

Examples

A size 3 diamond:

 *
***
 *

...which would appear as a string of " *\n***\n *\n"

A size 5 diamond:

  *
 ***
*****
 ***
  *

...that is:

"  *\n ***\n*****\n ***\n  *\n"