Five Hundred Years of Convergence: Leonardo da Vinci's Observations on Cardiac Vortex Flow, Water Spiral Dynamics, Flying Machine Design, and Sfumato as Prior Evidence for the V=N/D Density Wave Model

Between 1485 and 1513, Leonardo da Vinci made five systematic observations that constitute prior evidence for the V=N/D Density Wave Model (Katayama, 2025-2026): (1) spiral vortex blood flow in the sinuses of Valsalva and helical cardiac fiber architecture; (2) water always forms spirals at flow transitions (D-minimization); (3) human body proportions follow mathematical ratios (scale invariance of V=N/D); (4) flying machine designs extract the bird's N-high/D-low structure — the first documented engineering application of ephemeralization; (5) sfumato technique removes outlines so the void becomes productive — the visual prior for Ma (間) in V=N/D. The observational lineage: Leonardo saw the spiral (c.1513) → Torrent-Guasp mapped the fiber helix (2001) → Katayama derived the equation (2025). Version 2 adds the full flying machine / ephemeralization analysis.