This is a simple sweep picking lick i thought up for 3 string sweeping. It is very 
simple and good if you are new to sweep picking

|--------12-15-------------12-15--------|
|-----13-------13-------13-------13-----|
|--14-------------12-14-------------12--|
|---------------------------------------|
|---------------------------------------|
|---------------------------------------|
   d  d  d  u  u  u  d  d  d  u  u  u

Note: This is just an exercise, not a full lesson.