Tire Swing or Hammock Attached to a Tree on Shabbos



I just built a tire swing attached to a tree. I used one piece of string to attach to the branch. I then attached another piece of string to the first piece with the tire at the end. Also, the branch does shake a little when the kids are on it. Can we use it on Shabbos?



If the tree moves, then it is forbidden in any situation.



עיין שו”ת באר משה ח”ו סימן כט, שו”ת נשמת שבת הלכות זורע סי’ קסד וספר הלכות שבת השייכות לבית פרק יז ס”ה.