The Standard Model of particle physics does a remarkable job of explaining the particles and forces we observe in nature, but fundamental questions remain. Why are there three generations of particles? Why is the universe four-dimensional? What distinguishes the future from the past? Why are there both particles and antiparticles? Why are there precisely four fundamental forces? Why does spin exist? Our recent work suggests that these questions may have a single answer. We exploit the properties of the octonions, the largest of the four division algebras, to show how a single symmetry breaking principle reduces ten dimensions to four. In previous work, we showed how this principle naturally leads to precisely three generations of leptons. In our present work, we seek to generalize this construction to quarks, resulting in a unified model based on the symmetry group E6, or possibly its largest cousin, E8.