Since each quark is composite of spacetime charges, a nucleon (e.g. either proton or neutron) is further decomposed into spacetime charges. At the level of quark composition, a proton is made of 2 up quarks and 1 down quark, while a neutron is made of 1 up quark and 2 down quarks. Since an up quark is made of 5 H+ and 1 H- and a down quark is made of 1 H+ and 3 H-, at the level of spacetime charge composition, a proton is made of 11 H+ and 5 H-, while likewise a neutron is made of 7 H+ and 7 H-. The physical transformation of a proton into neutron can now be viewed as rearrangement of spacetime charges. However, although 11 H+ provide more than enough to arrange 7 H+, 5 H- would not be enough to form any arrangement of 7 H-. To satisfy this full arrangement, 2 H- must be borrowed from the quantum vacuum reservoir of spacetime charges. This need not be a full loan since the excess of 4 H+ can exchange as collateral with 2 H- of the reservoir. High energy experiments already determined that the up quark’s mass is between 1 to 5 MeV. And the mass of the down quark is between 3 to 9 MeV. From these experiment data the average mass of the down quark is twice the mass of the up quarks. Independent calculation has also determined that the coupling constant between spacetime charge of negative curvature and positive curvature is 2.01259 using proton mass of 1.673x10-27 kg and neutron mass of 1.675x10-27 kg and the facts that the proton is made of 11 H+ and 5 H- and the neutron is made of 7 H+ and 7 H- solving simultaneously two simple linear equations: (11H+)+(5H-)=1.673x10-27 and (7H+)+(7H-)=1.675x10-27 for H+ or H-. The solutions are H+=7.9428571x10-29 and H-=15.9857143x10-29. Dividing 15.9857143x10-29 by 7.9428571x10-29 gives 2.01259 to five decimal place accuracy. Geometrically, if the six spacetime charges composing the up quark are arranged as vertices of a regular polyhedron then the up quark can possibly be shaped into a regular octahedron. Likewise, the four spacetime charges of the down quarks as vertices can possibly be shaped into a regular tetrahedron. Geometrically speaking, transforming an up quark into a down quark is topologically equivalent to transforming an octahedron into a tetrahedron plus exchanging four positive curvature spacetime charges with two negative curvature spacetime charges from the quantum vacuum spacetime charges reservoir. The octahedron has 12 convex edges, while the tetrahedron has 6 convex edges. If the lengths of all these 18 edges are equal then the tetrahedron is considered more compact and hence more massive. At this level of spacetime charges arrangement, compactness of a particular spacetime structure is always inversely proportional to edge length of the corresponding polyhedron. In this sense, a strange quark is also a tetrahedron of shorter edge length than the down quark. A bottom quark is also a tetrahedron of shorter edge length than the strange quark. Likewise, a charm quark is also an octahedron of shorter edge length than the up quark. A top quark is also an octahedron of shorter edge length than the charm quark. Incidentally, wholesale exchange of spacetime charges from the quantum vacuum spacetime charges reservoir is also possible by exchanging a real octahedron with a virtual tetrahedron from the quantum vacuum reservoir. Unfortunately, wholesale exchange requires much bigger energy loan and by the Einstein’s quantum uncertainty of changes in time versus changes in energy whose product is always greater than or equal to a fixed factor of Planck’s constant of action, the large energy loan must be paid back to the quantum vacuum reservoir almost immediately. In other words, imitating the nature of spacetime charges rearrangement must not violate the physical principle of least action.