Funny, I knew how to do this when I was a lot more younger.
Before, like around 8, I got so pissed off at the shade, and ripped it right of the window!
OMG this happened to me yesterday.
my gran was like wtf are you doing pulling on the blinds like that ur gona break them.
then she explained.
i always thought it was a 50/50 draw like a trolly game of heads/tails