diff -r 0347e9bc883e -r 5d2c9d36da9d src/linetypes/quadrilateral.h
--- a/src/linetypes/quadrilateral.h	Sat Mar 03 16:59:03 2018 +0200
+++ b/src/linetypes/quadrilateral.h	Sat Mar 03 17:25:12 2018 +0200
@@ -28,7 +28,6 @@
 	static constexpr LDObjectType SubclassType = LDObjectType::Quadrilateral;
 
 	QString asText() const override;
-	void invert() override;
 	int numVertices() const override;
 	int triangleCount() const override;
 	LDObjectType type() const override;