Eric graciously linked us, implying, in what we hope is a tongue poking through cheek fashion, that the expressions "heh" and "indeed" uttered or written together or apart, are proprietary. Read the whole thing.™
The Man himself has echoed that sentiment, in his typical (which is not to say "trademarked") fashion.
Those stirring words are not the property of any one blogger, human, or bug-eyed monster from space. Think of them as Open Source Verbiage; the shared heritage of all thinking beings.
Ever has it been so, since that day in the dank recesses of prehistory when Grok the caveman was faced with the first attempt at taxation and faced the would-be despot down with a derisive sound, invented on the spot, that sounded much like "heh" as we know it. Grok's monogamous female life-partner, who would surely have been his wife had Church and State been around to codify and constrict the concept yet, always more verbally clever and less guttural with words than Grok, punctuated it with a parting "indeed" viciously hurled at the speed of sound in the general direction of the fleeing culprit's back.
Since there was no Senator from Disney to promulgate perpetual intellectual property to keep rights to the words in the Grok family name for the next thousand generations or so, and they were passed along at the speed of gossip until their origins were long forgotten, they came to be a generic part of human babble.
Nor are they associated with a commercial product in this instance, and therefore no trademark would apply. My partner and I care not if other people persist in using "heh" or "indeed," together or apart. We hope you won't either.