Ok, this is kind of a riddle game... so I cannot tell you how it goes, you have to figure it out. If you know this game, just play along so as to not ruin it for others.
It's called Green Glass Door. You have to figure out what does and does not go behind the Green Glass Door.
I'll give two examples to start us out, but form here on... only one per post, please.
Here goes:
Your feet are behind the Green Glass Door, but your toes are not.
The trees are behind the Green Glass Door, but the branches are not.
Feel free to private message me if you have questions and I will try to help without spoiling it for you.