What to read after Flatland?

As a satire, Flatland offered pointed observations on the social hierarchy of Victorian culture. However, the novella's more enduring contribution is its examination of dimensions; in a foreword to one of the many publications of the novella, noted science writer Isaac Asimov described Flatland as "The best introduction one can find into the manner of perceiving dimensions." As such, the novella is still popular amongst mathematics, physics and computer science students. The story is about a two-dimensional world referred to as Flatland. The unnamed narrator, a humble square (the social caste of gentlemen and professionals), guides us through some of the implications of life in two dimensions. The Square has a dream about a visit to a one-dimensional world (Lineland), and attempts to convince the realm's ignorant monarch of a second dimension, but finds that it is essentially impossible to make him see outside of his eternally straight line.