Michigan logos, a primer

The inspiration for this post comes from this post by Greg Dooley at MVictors. (If you don't already check out Greg on a daily basis, you should do so. He's exceptional at what he does.)
I also want to tip my hat to this MGoBoard thread which brought me to this place.

One of the things that has always fascinated me about Michigan is that it has had a variety of logos through the years, and even the Block M has had variations within any given space or time.   When I got the banner seen below for Christmas a couple of years ago, I became even more fascinated by the variations.

So, with this in mind, I am going to post several Michigan logos below, with captions. I will then discuss them below.