In 1984, luthier Linda Manzer developed the Wedge™ while designing the Pikasso guitar for Pat Metheney. The instrument, with four necks was quite wide and she wanted him to be able to see the surface of the guitar in order to play it. By tapering the back of the guitar she body pitched in toward the player, allowing him to better see the surface.
The accidental benefit was that the guitar was very comfortable to play. Since then, Linda has incorporated the design into standard models. The design has since been purloined by Taylor Guitars in their acoustic bass, Martin Guitars in an instrument project with Bill Cumpiano, and by other builders.
With her blessing, I offer the Wedge™ as an option on all my guitars and it comes standard on my JAB Acoustic Bass guitar.