Inspired by the observation posts described in Daemonslayer. Switches on the walls point to the vision slits they open/hide. 3 vision ports, each 2 blocks wide, the entrance is similarly concealed. Similar to the view ports it is concealed & that is activated by the lever on the same wall as the door. Iron door is opened by the buttons near to it, the entrance button is in a hollow space by the lower side of the door.

As a rule, remember that the switches will be attached & facing the wall relevant to its viewing ports.