shape morphing

First of all, create base shape in each frame which is triangle>square>pentagon>hexagon>circle

secondly, create another frame in between 2 shapes and create another layer to do guide line.

to create a straight line, using line tool to connects 2 shape's edges to form straight line and using that straight line create a center.

thirdly, using the guide line that I have created in scene to form shape by using pen tool

for the hexagon transform to circle is different.

copy the hexagon or duplicate the frame where pentagon is and paste in between the frame of pentagon and circle.

after that modify the hexagon, using selection tool to modify straight line to a bended line and not to forget to scale the shape in between the size of hexagon and circle. 

For my case, I wont need to do the scale as hexagon's edges are already pointed and caused intersect without crossed the line of circle.

once those steps were finished.

do the same again, but this time is create frame in between a shape and a "half-way" transformed shape.

reason to do that is to make the transformation smooth.

Finally, fill colors in the shape

triangle(red)>square(orange)>pentagon(yellow)>hexagon(green)>circle(blue)