↩ 🔵 🔵 🔵 ❪✺❫ Metrological Concepts ○ ❪∂₀❫ Portals ○ Metrology 𓆩⚪𓆪 ❪∂ᵢ❫ Time Math ○ ❪𝛿❫ Metrological Quantities ○