Go swimming by the rock. Swimming Pose that loops until exit.
Place back of rock right at shore line with the rock out in water the beach ball out in the water. Also the top of rock very slightly above the water line. Rotate and alighn the Beach Ball directly away from shore, ball about 1/2 submerged.
Minor adjustments may be necessary to fit your lake. Raise up down to have face just above water. Also needed is a fair sized lake or pond to place it in.