↩ 🔵 🔵 🔵 ❪✺₄❫ Mechanical Sets ○ ❪✺_❫ Mechanical Subs ○ ❪✺_ₛₛ❫ Physical Subsets ○ ❪✺_ₛₛ❫ Quantum Subsets ○ ❪✺_ₜₛ❫ Mechanical Typesets ○