A little pool with two layers of wall around it. One white and soft and the other dark and hard. Amidst a light brown grassy lawn with an outline of a green grass.
The answer to the riddle is a coconut. The reasoning behind this is that the two layers of wall represent the soft white inner flesh and the hard dark outer shell, while the light brown grassy lawn refers to the husk surrounding it, and the green grass outline represents the palm leaves found on a coconut tree.