"Close-up and realistic photograph of a cross-section of an oak trunk. The section must clearly show all the anatomical parts of the wood: the pith in the center, followed by the darker colored heartwood, the lighter sapwood, the thin layer of cambia, the book (or phloem) and finally the wrinkled bark on the outside. The growth rings should be clearly visible and detailed. The image should have an almost scientific quality, with natural colors and realistic textures of the oak wood section of the trunk should take up most of the frame, with a blurred background that suggests a forest setting."