[toth]

You probably are aware, but just to make it clear for others: topologically a torus has one hole (genus 1). The inner void is not considered a hole. Similarly, a 2-sphere (surface of solid sphere in 3d) has 0 holes (the inner void is not considered).

[adgjlsfhk1]

to be slightly more technical what you're defining as "voids" are often considered 2-dimensional holes (as formalized by homology)