fn tetra_volume(
a: CartesianCoordinates,
b: CartesianCoordinates,
c: CartesianCoordinates,
d: CartesianCoordinates,
) -> f64fn tetra_volume(
a: CartesianCoordinates,
b: CartesianCoordinates,
c: CartesianCoordinates,
d: CartesianCoordinates,
) -> f64