There are just only so many ways you can play in drop D using the pentatonic scale. Adam doesn't really have a very big bag of tricks, but he uses them well. Meaning; He's not a very good guitarist from a technical stand point, but he's excellent at trying unconventional styles of play and sculpting a perfect tone to keep things refreshing and sounding new.
Most of the time I don't even notice Adam has "re-used" some part of a riff until I actually start getting my hands dirty in the tabs and try to learn them.
This is actually a good interview with Adam concerning stuff like this. The 3rd to last question is really where they get into it.
I'm not saying this trying to make it sound like Adam sucks; I don't think that at all. I love his playing. I adore it actually. The level of perfection he has at controlling his tone is unreal to me. His use of his wah pedal, volume, delay, feedback... it's uncanny. He does have some technical ability too, dont get me wrong. His riff for Aenema where he taps the bar chords and does all the picking on the G and B strings in two different time signatures, and his triplet technique for the opening riff of Jambi are difficult things to master. I still don't get how to play Jambi... the CORRECT way.
Also, with regard to No Quarter specifically. Remember it isn't a note for note cover of the song. If No Quarter was a Tool song, this is what it would sound like.