# 3 Configurations of 9 Lines with 3 Intersection Points on each Line

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## Theorem

There exist exactly $3$ essentially different configurations of $9$ straight lines each of which has exactly $3$ points of intersection.

This is one: there are two others.

## Proof

## Also see

## Sources

- 1986: David Wells:
*Curious and Interesting Numbers*... (previous) ... (next): $9$ - 1997: David Wells:
*Curious and Interesting Numbers*(2nd ed.) ... (previous) ... (next): $9$