Write a program to display a two-dimensional, gray-scale "cloud" scene, where the cloud shapes are to be described as point patterns on a blue-sky background. The light and dark regions of the clouds are to be modeled using points of varying sizes and inter point spacing. (For example, a very light region can be modeled with small, widely spaced, light-gray points. Similarly, a dark region can be modeled with larger, more closely spaced, dark-gray points.)