Is it possible to script automatic shape/motion tweening?

I am new to AS. I would like to create a polygon that changes its shape (circle, trapezium, square, rectangle, triangle) based on specific buttons that the user clicks? An existing shape has to be able to morph into all the others. For instance, the trapezium has to morph to a square, circle, rectangle or triangle.

If I were to create each transition manually, I would end up with 5x4=20 scenes. Is there a way that I can just assign each shape to its own frame, and deploy actionscript to set in motion the transitions from one frame to the 4 other possible frames?

I am comfortable with either AS2 or AS3, and am using CS5. I am very grateful to anyone to just point me in the right direction, thanks!