Minkowski - Spherical - ⊚ - {t,r,θ,φ}      
  Minkowski - Cartesian - ⊞ - {t,x,y,z}      
  Schwarzschild - Droste - ⊚ - {t,r,θ,φ}      
  Schwarzschild - Droste - ⊞ - {t,x,y,z}      
  Schwarzschild - Raindrop - ⊚ - {t,r,θ,φ}      
  Schwarzschild - Finkelstein - ⊚ - {t,r,θ,φ}      
  Schwarzschild - Finkelstein - ⊞ - {t,x,y,z}      
  Reissner Nordström - Droste - ⊚ - {t,r,θ,φ}      
  Reissner Nordström - Finkelstein - ⊞ - {t,x,y,z}      
  Kerr - Boyer Lindquist - ⊚ - {t,r,θ,φ}      
  Kerr - Doran - ⊚ - {t,r,θ,φ}      
  Kerr - Kerr Schild - ⊚ - {t,r,θ,φ}      
  Kerr Newman - Boyer Lindquist - ⊚ - {t,r,θ,φ}      
  Kerr Newman - Kerr Schild - ⊞ - {t,x,y,z}      
  Gödel Universe - Cylindrical - ▭ - {t,r,φ,z}      
  Static Weak Field - Spherical - ⊚ - {t,r,θ,φ}      
  Rotating Charged Weak Field - Spherical - ⊚ - {t,r,θ,φ}      
  FLRW - Comoving - ⊚ - {t,r,θ,φ}      
  FLRW - Comoving - ⊞ - {t,x,y,z}      
  Vacuum De Sitter - Droste - ⊚ - {t,r,θ,φ}      
  Schwarzschild De Sitter - Droste - ⊚ - {t,r,θ,φ}      
  Reissner Nordström De Sitter - Droste - ⊚ - {t,r,θ,φ}      
  Kerr Newman De Sitter - Boyer Lindquist - ⊚ - {t,r,θ,φ}      
  General Metric - ◬ - Coordinate Independent      
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