The Pasch configuration is the unbalanced 
configuration (since
there are two lines through each of six points and three points on each of four lines)
illustrated above. Its Levi graph is the Pasch
graph.
Pasch Configuration
See also
Pasch's Axiom, Pasch Graph, Pasch's TheoremExplore with Wolfram|Alpha
References
Marušič, D.; Pisanski, T.; and Wilson, S. "The Genus of the GRAY [sic] Graph is 7." Europ. J. Combin. 26, 377-385, 2005.Referenced on Wolfram|Alpha
Pasch ConfigurationCite this as:
Weisstein, Eric W. "Pasch Configuration." From MathWorld--A Wolfram Web Resource. https://mathworld.wolfram.com/PaschConfiguration.html