I am 6'4" and the attic is, well, short. And I learn slowly. As a result, I repeatedly banged my head on the door sill, which is 6' in that attic. (It's not quite as lame as it sounds; with things at a certain height, just between 6' and 6'6", they are just high enough to be out of my vision, and not high enough to clear.)
Worried about my continued health, Beth made this sign for me to hang on the door sill. She thought it was just a lame little joke reminder; I think it is art.
So here, years later, is that art for others to enjoy. I've posted in two formats: The original that she did (which was not in color) and a PDF version you can print if you need your own warning. I've cleaned that up a bit, put in text in font, rather than her original drawing, and added colors.