Nimbostratus cloud
Under Luke Howard's first systematized study of clouds, carried out in France in 1802, three general cloud "forms" were established based on appearance and characteristics of formation: "cirriform," "cumiliform" and "stratiform." These were further divided into upper and lower types depending on altitude. In addition to these three main types, Howard added two names to designate multiple cloud types joined together: "cumulostratus," a blending of cumulus clouds and stratus layers, and "nimbus," a complex blending of cirriform, cumuliform, and stratiform clouds with sufficient vertical development to produce significant precipitation.
Cloud (video game)
The game contains three types of clouds: white clouds, which follow the avatar; gray, neutral clouds, which become white when touched; and black clouds, which may be combined with white clouds to cause rain, dissolving both clouds. A large number of white clouds more easily dissolves a small number of dark clouds than an equal number, and vice versa. White clouds stop following the avatar if the player moves too quickly and they resume following if approached again. Each of the four missions in "Cloud" has a different objective, including forming patterns in the sky with clouds, eliminating black clouds, and creating rain over each of the islands.