diff -r d891da20abca -r 6ad27b7d2697 src/invert.h
--- a/src/invert.h	Wed Jun 29 14:11:58 2022 +0300
+++ b/src/invert.h	Wed Jun 29 14:43:42 2022 +0300
@@ -26,9 +26,32 @@
 {
 	glm::mat4 flipmatrix(Axis dimension);
 }
-//void invert(LDObject* obj, class DocumentManager* context);
+
+constexpr void invert(Quadrilateral& quad)
+{
+	std::swap(quad.p1, quad.p3);
+}
+
+constexpr Quadrilateral inverted(Quadrilateral quad)
+{
+	invert(quad);
+	return quad;
+}
+
+constexpr void invert(Triangle& tri)
+{
+	std::swap(tri.p1, tri.p2);
+}
+
+constexpr Triangle inverted(Triangle tri)
+{
+	invert(tri);
+	return tri;
+}
 
 namespace gl
 {
 	void invert(PolygonElement &polygon);
 }
+
+using gl::invert;