The Selected Works of T. S. Spivet include drawings, charts, and lists accompanying the written elements. These drawings are purported to be done by T.S. himself, who also provides each with an explanatory caption that deepens the book's narrative. This is designed to mimic T.S.'s own habit of quantifying the world around him using cartography. Larsen has stated that this technique was not originally intended to be included in the book's format, finishing a complete first draft of the work before he "discovered the margins as a playground of T.S.’s mind." Larsen's parents were both visual artists (his mother a painter and photographer, his father a printmaker),
Geodesic deviation "geodesic". The "geodesic deviation equation" relates the Riemann curvature tensor to the relative acceleration of two neighboring geodesics. In differential geometry, the geodesic deviation equation is more commonly known as the Jacobi equation. To quantify geodesic deviation, one begins by setting up a family of closely spaced geodesics indexed by a continuous variable "s" and parametrized by an affine parameter τ. That is, for each fixed "s", the curve swept out by γ(τ) as τ varies is a geodesic. When considering the geodesic of a massive object, it is often convenient to choose τ to be the object's proper time.