In Reason, I like to take a drum loop in Dr. Rex, set the L&R markers in the Dr. Rex track to (often) 8 bars, then click the “To Track” button, which puts in the MIDI notes to play back the loop. I’ll then select a bunch of the notes in the last measure and from the Tools window apply “Alter Notes.” If you loop those 8 bars, there’s a variation in the last measure that gives a turnaround, or can be fine tuned to create a roll or similar. Using Alter Notes doesn’t change the pitch, just the timing, making that last play-through a bit unexpected. Just what’s needed to help negate the constant repetition. Each time you use the tool you will get a slightly different result. Set the amount to 60% or larger to make things even less predictable. Either Undo and Redo or apply the effect multiple times until you get what you want…