Generally if you have noise, you want a water feature to cancel the noise out with "white noise." You might also consider sound proofing your windows.
high fencemad dog
nosy neighbors security Kids Dog pool
fence, dog, camera, trees, trespassing sign, bushes, sprinkler
pigs
fence dog camera tree bush trespass sign
It's most likely for decoration.
The treadmill itself isn't particularly noisy, but running on it will likely be able to be heard through the floor. If your downstairs neighbors have sensitive ears, it might be possible to find some foam padding to put under the treadmill to dampen the sound.
Complain to the landlord.
Where I grew up, you might get your yard rolled with toilet paper or eggs thrown at the house. One year as a trick, some neighbor boys put people's lawn furniture on top of their roofs.
experience conflicts, lack trust, and have communication breakdowns which can escalate the situation even further.
you get a large sifter and sift medium sized portions( about 5-6 cups) then put sifted soil in a seperate bucket and sift the rest then when stones are removed put them in your neighbors yard... secretly
food i guess if you put it in your yard it might keep other Raccoons away