Hi Pavel, > public Affine(double[] matrix) > // accepts arrays of length 6, 12 and 16. > // In case of 16 members the last four numbers must be 0, 0, 0, 1 > // throws IllegalArgument if the above conditions are not met What is the point of setting 4x4 matrix of the last row must be 0,0,0,1 ? Should we remove 4x4 case at all ? Thanks