The Hidden Complexity of Drawing Graphs
A graph's complexity is not just about its lines and dots, but how many times those lines cross. Surprisingly, finding the minimum number of these crossings is an incredibly difficult mathematical challenge.
Mathematicians define a graph as planar if it can be drawn without any edges crossing at all. However, as graphs become more connected, preventing these overlaps becomes nearly impossible. Researchers study these crossing numbers because clear, clean layouts are vital for helping humans understand complex data networks. It turns out that organizing visual information is a deep problem rooted in pure geometry.
Source: Crossing number (graph theory)