Due to the fantasy nature of most anime robots, and the necessary simplicity of cel-animated designs, mecha models lend themselves well to stylized work, improvisations, and simple scratchbuilds. One of Gundam 's contributions to the genre was the use of a gritty wartime backstory as a part of the fantasy, and so it is almost equally fashionable to build the robots in a weathered, beaten style, as would often be expected for AFV kits as to build them in a more stylish, pristine manner.