This is where Type O got it from. Awesome, not my favorite Sabbath but easily an 8/10.
Here's a classic from a different era:
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@Metalhead Steve: not saying some djent bands don't have progressive tendencies. It's a forward-looking style. But the "prog" label is taken by stuff like Rush, King Crimson, or Yes that had very strong technical chops and jazz influences, and/or metal bands that picked it up and ran with it. That Descending song was pretty derivative of other modern metal and didn't show any direct prog influence.