x1=st1 is direct / directly x2=st2=se3, with single / clear relationship / step x3=se1 of type x4=se2; x1 is straightforward / without layered interruption.
x1=d2=st1 is indirect / indirectly x2=d1=se3, with layers / steps x3=se1 of type / material / manifestation x4=se2 separate / interrupted from the direct layer due to quality x5=d3.