A user in global chat named 3clipa stated that build mode was quite difficult while on mobile. They said that the developers should "make it so when you press on an item you can copy it there" 3clips is most likely referring to wanting a button next to the rotation button to clone something. I will have an image representing that in an attachment. Adding this feature for mobile users could help many players and especially 3clips. I hope this helps, as I like to help the community and the game.