Abstract A known result in combinatorial geometry states that any collection P
n of points on the plane contains two such that any circle containing them contains
n/c elements of P
n,
c a constant. We prove: Let Φ be a family of
n noncrossing compact convex sets on the plane, and let
S be a strictly convex compact set. Then there are two elements S
i, S
j of Φ such that any set S′ homothetic to
S that contains them contains
n/c elements of Φ,
c a constant (S is homothetic to
S if 5’ = λS + v, where λ is a real number greater than 0 and v is a vector of ℜ
2). Our proof method is based on a new type of Voronoi diagram, called the “closest covered set diagram” based on a convex
distance function. We also prove that our result does not generalize to higher dimensions; we construct a set Φ of
n disjoint convex sets in ℜ
3)3 such that for any nonempty subset Φ
Hh of Φ there is a sphere S
H containing all the elements of Φ
H, and no other element of Φ.