brain teaser for the day:
you have two env~ objects, listening to two different audio sources, and you want to add the two resulting envelopes. the problem is, you need know which env~ will output last during each frame so that you can attach it to the first inlet of the + object. otherwise, you get the situation where you are actually adding the envelope of the current frame of one signal to the envelope of the previous frame of the other signal.
i don't think there is an answer (where "depends on creation order" == undefined == not an answer), but if there is one it would be nice.
pix