The ornamental design for spa with bi-lateral flanges and lateral flares, as shown and described.
FIG. 1 is an upper perceptive view;
FIG. 2 is a top view;
FIG. 3 is a first side view;
FIG. 4 is an enhanced view of a left portion of FIG. 3;
FIG. 5 is a second side view;
FIG. 6 is an enhanced view of a left portion of FIG. 5;
FIG. 7 is a third side view; and,
FIG. 8 is an enhanced view of a left portion of FIG. 7.
The broken line showing of parts of the drawings is included for the purpose of illustrating use and environment and forms no part of the claimed design.