Construct a chain of six circles, all tangent to a seventh circle and each tangent to its two neighbors. The seven circles theorem guarantees that the three lines drawn between opposite pairs of the points of tangency on the seventh circle, all pass through the same point.
Several variations are possible, such as circles externally tangent to the central one, and other combinations.

Construct a chain of six circles, all tangent to a seventh circle and each tangent to its two neighbors. The seven circles theorem guarantees that the three lines drawn between opposite pairs of the points of tangency on the seventh circle, all pass through the same point.

Several variations are possible, such as circles externally tangent to the central one, and other combinations.