I do not know why it's a triangle.
This explains the algorithm they use to generate the keyscape: extras.humdrum.org/man/mkeyscape/
I don't see why it couldn't be a rectangle. Obviously the 2d representation is important because the notes fit multiple keys, so for each measure or whatever time interval, it has to display the keys that the notes in the score support.
And it has links at near bottom to ones of Motzarntz and Bakch and the other great composers like you were asking about. I skimmed them quickly looking for CDCs, but didn't look to close.
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the prick of misery pierced my foot on a spiiiike on, Sat 17 Mar 2012, 1:26,
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