How Could I Randomly Generate a Tower for My App?

I am currently working on making an app where you complete different levels that consist of falling down different towers and dodging obstacles in order to reach the bottom. As of right now I have no idea how I could use a script to generate a tower for me and was wondering if I could get some help either creating or learning how to make a script that could do this. As of right now each of my wall segments is 7x5 units. Each unit in my game is 80x80 pixels. I also have some bricks that the player must dodge that are 1x1 units. If I need to post any more information please let me know.