You can do the same with @jeffalo’s upside-down button, but the URL needs to be ‘javascript:(function(){['', '-ms-', '-webkit-', '-o-', '-moz-'].map(function(prefix){document.body.style[prefix + 'transform'] = 'rotate(180deg)';});}())’

Works on most webpages. Seems to unload elements on others.

You could make both of these happen whenever you load the page with the Tampermonkey extension. Don’t know why you would want to though.