I found a millstone in the river that runs past our house and wanted to move it into our garden but it's pretty heavy. It took quite a bit of thinking but in the end we have found a way to move it using a long lever and some physics. Basically we flipped it over and over and over .....

The principle is that the applied torque must be bigger than the torque of the weight about the pivot. This is achieved by using a long lever and pulling perpendicular to it.

Here you can see the Forces the pivot is the right corner of the stone so you can see that the stone should turn since the perpendicular distance from the applied force to the pivot is greater than from the weight to the pivot. Note that in reality the applied force is no where near as big ad the weight so a long lever must be used.

One interesting thing was that the stone was much easier to flip when it was curved side down. We can see why that is. When the flat side is down the pivot is the right corner but when the curved side is down the pivot is the point where the surface touches the ground, much closer than the corner

When the stone was vertical it was quite easy to push over but if it was not quite vertical it was not so easy. We found that if the stone was moved back and forth it was easier to push over. This is similar to a resonance effect but I'm not sure of the explanation.