Triangles, Circles and Squares

I have to admit I've never understood the care instruction symbols on clothing. For the most part, this isn't a major issue, as garments are also conveniently labeled in English. However, for a select few items no such instructions are provided, and I'm stuck interpreting a strange pattern of circles, squares and triangles, as well as the occasional iron. Anyway, today I was looking at my winter hat, which had an X thru a quadrangle of some sort, an iron with 110c written on it and a circle. So, lacking any idea what these meant (except of course the iron), I went to the web. Anyway, just wanted to pass along the following if any of you are curious. I had no idea so many symbols existed. Not sure what I would have done without the Textile Industry Affairs Group.