After effects question

If i wanted to unroll a triangle onto the screen how would i go about that in after effects?

am i asking in the wrong form? or do i need to clarify what i am trying to do?

Basically what i want to do is take a flat image and roll it up and have it kinda unroll flop on to the screen. and then roll back up.

I have been searching on the internet, but having come up with anything usefull...