The Grünbaum configuration is the term used in this work for the geometric
204 configuration constructed by
Grünbaum (2008) and denoted by Berman et al. (2024). It consists of 20 points and 20 lines, with four points on each line and four lines
through each point. Its construction disproved the conjecture
of Grünbaum and Rigby (1990) that no geometric n4
configuration exists for .