Any small amount of convexity along the grey border will cause an example to fit right.
Any convex corner or small amount convex curvature along the grey border will cause an example to fit right.
No straight path passes from a white region to a grey one, then to white again (without hitting black) vs. such a path exists.
No straight path passes from a white region to a grey one, then to white again (without hitting back) vs. such a path exists.
No straight path that passes from a white region to a grey one, then to white again (without hitting back) vs. such a path exists.
Leo Crabbe