I will try to describe what the invention does, but please bear in mind that I am as far from an engineer as you could get.

This device, I can assure you, is just about the most impressive piece of engineering you will find anywhere. I cannot say I have seen first-hand how it works, I've only seen the finished product this thing is designed to make; but apparently it goes something like this:

The device is taken to the location where the building construction is required. It is placed on the ground and activated. You only have to press a button; the device does everything else by itself. 

Some cylindrical tubes emerge from the bottom of the device and embed themselves into the ground; and it then proceeds to extract the minerals, water, and other substances from the earth. 

The device then opens out, lengthwise flat on the ground, until it reaches the full required length of the building. It then begins to open out at right-angles, expanding until it forms the building’s width. This process continues until the device returns to the point at which it began, and the foundation of the building and the inner layout is thus established. 

The device then collects a much larger amount of required materials, before resuming its expanding process. This time it expands upwards, until the walls of the building are formed. During this time, apparently, the device also has the facility to include the doors and windows of the building. And finally a substantial roof is added. The entire procedure occurs at an alarmingly speedy rate by any standards.

I have been an admirer of this device for so long now, and I’ve tried hard to explain it to family, friends, and acquaintances, even strangers. Needless to say, the reactions have been many and varied. Usually sceptical.