The material of this door is a special type of board used when casting with concrete . Its very water resistant and can be under water for a long time .The window is 3mm not so stiff plastic.
The inside-piece and the Turtle shell door are fit together with four hinges. (both left and right ones on the same side, so it not will fall off
The right ones are mounted upside down ,
The door is two almost equal pieces with a 3mm plastic "window" in between . I have used a Dremel tool for the artistic work .
There´s a track for the "door-rope" at the backside of the outside door- piece . Buy pressing the rope into this track and tighten with screws all around it will stop the rainwater from dripping in at the doorway .
Here are the both pieces that makes the door .