The ITEM() function with MDX code examples

I usually write MDX blog posts with a business problem as the start point and seldom posts about how MDX functions might work.  Here is one exception, the Item function that is useful in many analytic scenarios,  will be discussed with examples but only in an attempt to explain how it works.  I thank Chris Webb for helping me on some questions that I had.
 
We will start with a query to get a base result set to use with the Item function in the later examples. Run this MDX in management studio: