in particular in the second interval both a and b should be flatted in the third there is no g in the original tetrachord in the fourth and fifth there is no b natural in the original tetrachord in the sixth there is no a natural in the original tetrachord i'm also not aware of webern or schoenberg using this tetrachord much explicitly there might be a few of them here or there in their music but i'm pretty sure it's not a significant feature of either's music as it certainly is in carter i don't know about perle i don't think either webern or schoenberg even knew of the special properties of this tetrachord the literature on webern and schoenberg that i know certainly doesn't mention this mind providing citations finally the second external link is dead it's also questionable carter's night fantasies is usually cited as the quintessential example of registrally deployed all interval twelve tone series quite a different phenomenon than all interval tetrachords there might be all interval tetrachords within it though it'd be nice to have the link fixed so we can see