Dynamic symmetry is a proportioning system and natural design methodology described in Hambidge's books. The system uses dynamic rectangles, including root rectangles based on ratios such as √ 2, √ 3, √ 5, the golden ratio (φ = 1.618...), its square root (√ φ = 1.272...), and its square (φ = 2.618....), and the silver ratio ( δ δ s = 2.414... ).