On the simplicity of numbers

The recent measurements of reactor antinu_{e} disappearance and its interpretation in terms of the three light neutrino mixing angle {theta}_13 by the DAYA BAY \rightarrow {theta}_13 = (8.83 + 0.81 - 0.88) \circ and RENO \rightarrow {theta}_{13} = (9.36 + 0.88 - 0.96) \circ collaborations, gave rise to this treatise, upon the hypothetical substitution {theta}_13 \rightarrow \vartheta_9 = 9 \circ. The latter angle (\vartheta_9 = 9\circ) is related to interesting algebraic properties of its periodic functions, which in turn have their origin in the discrete symmetry groups S5 = Z2 \times A5 and A5, the point groups associated with the regular d = 3 'Platonic bodies' : dodecahedron and icosahedron. How these discrete groups may be related to dynamical symmetries of mass and mixing of light neutrino flavors is left open.