I see some pumpkins with designs all the way around, but I can't seem to turn mine to carve on the back.  Also, I read I can shrink/grow when looking around? Is that how people get their pumpkins on the roof? 

Sorry I don't list the controls anywhere!
To turn your pumpkin, right click or middle click and drag the mouse.
The shrinking / growing is a hidden feature, but you can do it by finding and clicking on a magic mushroom.