Question 2
Decide whether it possible to cover all lattice points in $\mathbb{R}^2$ by an (infinite) family of disks whose interiors are disjoint such that the radius of each disk is at least $5$.
Proposed by Gregory Galperin; source discussion: https://aops.com/community/p825495
Proposed by Gregory Galperin; source discussion: https://aops.com/community/p825495