Help! I'm trying to tessellate a shape with random vertices

I am able to create a shape and tesselate it (using a for loop) when I have a FIXED number of vertices on the top/bottom and sides.

However when I try using a random number of vertices for top/bottom and sides, when I go to tesselate the shape, the randomness changes every time thus the tessellation fails.

What’s the best way to set this up?

Once I create a shape using randomness, how do i duplicate and move the the shape without the randomness regenerating new numbers?