The cell has a basalt generator for the walls and floor. The floor is covered in water and the prisoner respawns from above using the 2-chamber design. A guard can look at the prisoner through iron bars and glass, but this can be shut off. The prisoner can also be given bread from a dispenser.
Outside defence
The prison is surrounded by area kickers and wither-resistant walls. The roof has a mining detector, as well as cow player detectors, and the floor has a pearl glitch detector. There are many unbanned trap portals above the prison, so directly spawning a portal inside is somewhat time-consuming.
More security
The visiting hallway includes a boat to respawn the visitor higher up, making item smuggling much more difficult. A suicide switch can be used to permanently ban the entire prison. The guards have many composter machines to see things. The guard tunnels in most places are one-directional, and near the end is a room they can use to call themselves back with a stasis chamber.
