"It was the last day of the 1999th year of our era. The pattering of the rain
had long ago announced nightfall; and I was sitting in the company of my
wife, musing on the events of the past and the prospects of the coming
year, the coming century, the coming Millennium."
Those words appear near the beginning of the 15th chapter of a remarkable
book titled Flatland: A Romance of Many Dimensions.
Written in 1884 by Edwin A. Abbott (1838–1926), this slim volume has long
served as a doorway to the fourth dimension and beyond for many explorers
of geometry. The books central figure and narrator, "A Square," takes