Instrumental Duet Bassoon,Clarinet,Instrumental Duet - Level 4 - Digital Download SKU: A0.980499 Composed by Bob Atwell. 20th Century,Contemporary. Score and parts. 16 pages. Bob Atwell Music #3541741. Published by Bob Atwell Music (A0.980499). This is a short fun piece for Clarinet and Bassoon. It is (obviously) based on Bach's 2 part invention #4 but with a lot of original material added.