10. Close Packing of Spheres

The text explains the concept of close packing of spheres, a principle that describes how spheres can be arranged in three-dimensional space to achieve the densest possible packing. It highlights the two primary lattice patterns used in this arrangement: the square lattice and the hexagonal lattice. The text then explores the relationships between these patterns, including how they relate to orthogonal and tetragonal planes and axes, and how these relationships are used to define a more complete coordinate system. The text concludes by emphasizing that the close packing of spheres represents a foundational concept for understanding space, matter, and spatial structures.