Dear Futura, I love you - but you can seem a bit too starched from time to time. Justin David Cox seems to agree. I'm guessing it's meant to look like an envelope, but if not I still like. He adds "Please note that calling Paul Renner lazy is supposed to be so absurd that it can’t be taken seriously. That said I still think the C is the weak point of the most beautiful typeface ever created." Check out his blog here.