Nim can be so difficult to understand

[HJarausch]

I'd like to create two objects hold a ref to the same _Matrix_ , what am I 
missing?

Many thanks for a hint!
    
    
    type
      Matrix[T] = ref object
        data : seq[T]
      
      MX[T] = object
        Theta : ref Matrix[T]
      
      MXU[T] = object
        Theta  : ref Matrix[T]
    
    var
      M  : MX[float]
      MU : MXU[float]
    
    M.Theta= new Matrix[float]
    
    #[ gives type mismatch: got 'Matrix[system.float]' for 'new Matrix[float]'
       but expected 'ref Matrix[system.float]'
    ]#
    
    M.Theta.data= new seq[float]
    
    M.Theta.data = @[1.0,2.0]
    
    MU.Theta = M.Theta   # do both point to the same matrix?
    
    MU.Theta.data[0]=7.0
    echo M    # I'd like to see  [7.0,2.0]
    
    
    Run