Studies of Euler diagrams/logota

This function can be represented in one dimension closed to a circle. The corresponding graph is an octagon. (Compare Studies_of_Euler_diagrams/gapspots/hard_and_soft.)

In a 2-dimensional representation the borders intersect in a single point. (Compare Studies of Euler diagrams/foravo, the equivalent with 3 sets.)

Shown on the right is one way represent it with separate border intersections, resulting in 3 gapspots.