public static ref Vector3Wide GetUpperRight3x1Block(ref Symmetric4x4Wide m)
 {
     return(ref Unsafe.As <Vector <float>, Vector3Wide>(ref m.WX));
 }
 public static ref Symmetric3x3Wide GetUpperLeft3x3Block(ref Symmetric4x4Wide m)
 {
     return(ref Unsafe.As <Vector <float>, Symmetric3x3Wide>(ref m.XX));
 }