We set friction to zero and the tower simply left

There is a panel of sliders in the development build, and one of them is friction. It normally sits at zero point seven, which is roughly what you would expect from a wooden block on a wooden block. We pulled it to zero to see what would happen, rebuilt the tower, and then spent the next few seconds watching fifty four blocks discover that nothing was holding them.

The interesting part is where it starts. It does not topple. Toppling is what a tower does when it leans too far, and leaning requires the bottom to stay put while the top goes somewhere. With no friction the bottom does not stay put. The lowest rows squeeze outward under the weight above them, each block sliding along its neighbour like a bar of soap in a fist, and the tower sinks into itself while the top four rows are still perfectly stacked and completely unaware.

That is the picture above, taken about a second in. The top of the tower still looks like a tower. The bottom looks like something that has been left in the sun.

One second later there is a two row stump on the plinth and blocks all the way out to the walls, which is the first time the new walls have properly earned their keep. Then it goes quiet, and you are looking at a very tidy floor with a lot of mess on it.

Zero point seven it is, then.