Don’t click “checkout” on an infinite pack of Jenga blocks just yet. Real-world practicalities such as irregular block shapes, air currents and the crushing weight of an endless edifice may hamper your engineering aspirations. Still, understanding why the overhang has no limit in an ideal mathematical world is enlightening. The explanation hinges on math’s harmonic series and the physics concept of center of mass, two seemingly simple ideas with outsize power. [For more fun, check out: How Tall Can You Build a Tower without It Toppling?]