Emerson has a legal claim on the wave, but I don't remember if it's both patented and trademarked. But I do remember reading that Emerson has asked people not to add waves on a commercial basis. Cut a wave in your own for your own personal use, and nobody can get in a twist. Make it a business transaction, and things get legally stickier. Same thing with a Spydie Hole; do what you want with your own knife, just don't be surprised to gather attention if you offer a "Make It Like Spydie" service. They could have made it look like a batwing, lightning bolt, or hired a graphic artist to come up with an aesthetically different design. Instead, it looks like a copy of Emerson's IP. CS had the good graces to "wave" their openers with a thumb plate instead of an outright copy. Who knows, maybe Snaggletooth got permission and pays royalties, they are certainly charging enough.