genuinely challenging, entirely mysterious...,

wikipedia | Charles Howard Hinton (1853, UK – 30 April 1907, Washington D.C., USA) was a British mathematician and writer of science fiction works titled Scientific Romances. He was interested in higher dimensions, particularly the fourth dimension, and is known for coining the word "tesseract" and for his work on methods of visualising the geometry of higher dimensions.

In an 1880 article entitled "What is the Fourth Dimension?", Hinton suggested that points moving around in three dimensions might be imagined as successive cross-sections of a static four-dimensional arrangement of lines passing through a three-dimensional plane, an idea that anticipated the notion of world lines, and of time as a fourth dimension (although Hinton did not propose this explicitly, and the article was mainly concerned with the possibility of a fourth spatial dimension), in Einstein's theory of relativity. Hinton later introduced a system of coloured cubes by the study of which, he claimed, it was possible to learn to visualise four-dimensional space (Casting out the Self, 1904). Rumours subsequently arose that these cubes had driven more than one hopeful person insane.^{[citation needed]}

Hinton created several new words to describe elements in the fourth dimension. According to OED, he first used the word tesseract in 1888 in his book A New Era of Thought. He also invented the words kata (from the Greek for "down from") and ana (from the Greek for "up toward") to describe the two opposing fourth-dimensional directions—the 4-D equivalents of left and right, forwards and backwards, and up and down.^[11]

Hinton's Scientific romances, including "What is the Fourth Dimension?" and "A Plane World", were published as a series of nine pamphlets by Swan Sonnenschein & Co. during 1884–1886. In the introduction to "A Plane World", Hinton referred to Abbott's recent Flatland as having similar design but different intent. Abbott used the stories as "a setting wherein to place his satire and his lessons. But we wish in the first place to know the physical facts." Hinton's world existed along the perimeter of a circle rather than on an infinite flat plane.^[12] He extended the connection to Abbott's work with An Episode on Flatland: Or How a Plain Folk Discovered the Third Dimension (1907).