Setting up was easier than finding the materials. I bought some plastic trays, a red light bulb, and darkened the second bathroom – to Westerners, a cubicle with a squat toilet, a wall tap and a shower. The toilet functions as drain for all three.
There was a full door that actually shut well, and a “window” made of concrete vents. I used cardboard boxes to cover the vents, and shoved paper in the door frame gaps. I got good darkness by adding a curtain of blankets. I could only stay there a few minutes for lack of air. The table was made of a tin box placed on top of the toilet.
I had a clock outside, and started the tests.