Music Made From Memories Charles Ives' Holiday Symphony

I think the comments on the shadow lines are interesting: hardest for us to understand, yet widely used by Ives. What was he hearing? I recall that the presence of the shadow lines in the 3rd Symphony--in some versions--has been used to criticize Ives's meddling with his older scores, as though his purpose was simply to "jack-up the dissonance" to compete with other modernist composers of the time. But he does it so widely, surely there is something else going on. It takes good performances to come to understand what that purpose could be.