You would dig a square trench that is 1 meter deep and add a wall that is 1 meter above ground and a wooden roof above it. The trench plus the wall adds up to just under 2 meters if you take into account the floor and roof thickness. Above that would be clear plastic panels so you would have a box within a clear box, the inner box would be a man-cave with a projector and recliners and a small partition for a tiny box office. The ceiling of the man-cave would have pot boxes on it to grow tomatoes. It would look more like a table than top portion of a room.
I was looking at the raspberry pi zero version 2 and noticed it had a 64 bit processor and only half a gig of ram; I laughed because we switched to 64 processors so we could run more than 4 gigabytes of ram. I guess the 64 bit processor is for software compatibility so you can run the same OS system as the more advanced versions of raspberry pi. It is not bad for something that is roughly £10 in value. You can have full working pc for a tenner. The thing is about the size of a credit card. It could be the computer I use in the sunken office.
My imagination never rests.
