The good folks over at Guitar World want to make sure you know the difference between the half/whole and whole/half diminished scale, and they’ve employed Revocation’s Dave Davidson to be your tutor on this subject. Dave just so happens to have a riff that used both of these and therefore is the perfect pedagogical tool for this application.
In case you are unaware, there are two types of diminished scales: one that proceeds half step, whole step, half step, whole step, and so on, and one that is the inverse of that – whole step, half step, etc. They’re both called “symmetrical” scales for this reason, and each one repeats itself exactly every minor third, which makes them very appealing to play on the guitar, because you can move any figure up three frets and it will still be inside the scale.
Now that you’re thoroughly confused, here’s Dave to un-fuck your brain.
via Guitar World