The old washing machines
would be bolted to the floor, but this was a real pain, so we instead fit iron ore weights either bound with clay or cement, and an arrangement of springs, so the drum can move but the body remains reasonably static.
I was involved with making these weights, which were made with a press, in my case using cement to bind the iron ore together, it made around 6 weights per minute, and we have a box which filled with a set amount of mixture to drop into the mould, but the problem was some times a bit of concrete mix would stick in the box so the weight was pressed with a short measure.
The concrete forms some flashing, so when the thin blocks were fitted, they felt tight, but in use the flashing would crumble, and the weight would come loose, we tried to fit alarms to show when the press was going down to far, but it did not always work. Should one weight be loose, then the machine can walk through the kitchen, today sensors are fitted on the machine, to auto stop it if it vibrates too much, but they will always move a little, but as long as legs adjusted correctly should not move much, however on a flexible floor clearly they will move more than on a solid floor, and if weights are loose then it can get daft.