I'm looking for a marimba piece that has a technical focus on double lateral strokes, but here's the catch: I'm fine with the 1-2 pattern... I need to work on the 2-1 pattern (left hand). Does anyone know of a piece that uses the 2-1 pattern?

Just make up exercises, or if you don't want to, look in the Stevens book.

I would recommend Gordon Stout's Beads of Glass. The piece utilizes inside and outside double lateral strokes from beginning to end.This is a piece that I recommend time after time to students who seek what you are seeking because of it's musical capabilities as well as the technical exercise. The piece is very beautiful; a real crowd pleaser and a great opener to any recital.

TAB