Diamond Kata

Proposed by Seb Rose http://claysnow.co.uk/recycling-tests-in-tdd

Problem Description

Given a letter, print a diamond starting with ‘A’ with the supplied letter at the widest point.

For example: print-diamond ‘A’ prints

 A  

For example: print-diamond ‘B’ prints

 -A-  
 B-B   
 -A-  

For example: print-diamond ‘C’ prints

--A--  
-B-B-  
C---C  
-B-B-  
--A--