Dissolve the gelatin in water according to package instructions.
In the bottom of a lightly oiled ring mold arrange a pattern of avocado slices and grapefruit sections.
Pour in some of the gelatin mixture and chill until set.
Arrange the rest of the avocado slices and grapefruit sections with the figs to fill up the mold and add the remaining gelatin.
Chill until firm.
Unmold the salad on a serving plate, surround with crisp torn-up lettuce, and serve with mayonnaise.