The derivation begins with a single physical input — the Lyman-limit wavelength of hydrogen — and, through a four-circle geometric construction using only the radian conversion factor and the fine-structure constant, produces the speed of light as a pure distance requiring no clock. The same framework, applied in reverse, derives Planck's constant from hydrogen's ionisation energy. The two constants emerge as exact reciprocals: every geometric factor in one is inverted in the other. T
David Charles (Fri,) studied this question.