I don't know the details of how they become grits, but they are also known as hominy grits, and hominy has something to do with corn.

 

I think they are ground up like corn meal, but I did learn to eat them AND like them when I lived in Florida.  They are usually eaten with your eggs, bacon etc. for breakfast.  You can add cheese to them and they are delicious, or just plenty of butter or margarine, salt and pepper.  They are hard to find in some states.  I don't think I'd ever seen them until I moved to Florida with husband #1.