This is a Prison My friend and I built over the past week or so. It has 18 Cells, each open individually but close together, and a combination lock in the back that opens to a small room with 6 large chests. The combo is 3 9 8 7, then press enter and the door opens, then to close the door and reset the lock, press the button to the left of the door.
It is recommended that you make a whole 135W, 148L, and 19H, first then importing the prison in to make the entrance level to the ground. (Sorry i had originally made it inside of a mountain, but i can't put the whole mountain in.) Or you could build a ladder up to it..
Feedback of what you think, and things i could improve on, and ideas are always appreciated :)