diff -r 764381756899 -r 62373840e33a src/linetypes/quadrilateral.cpp
--- a/src/linetypes/quadrilateral.cpp	Wed Mar 11 19:05:34 2020 +0200
+++ b/src/linetypes/quadrilateral.cpp	Tue Mar 17 23:13:29 2020 +0200
@@ -87,3 +87,20 @@
 	// -> 2 1 0 3
 	std::swap(this->points[0], this->points[2]);
 }
+
+int ldraw::Quadrilateral::numPoints() const
+{
+	return 4;
+}
+
+const glm::vec3& ldraw::Quadrilateral::getPoint(int index) const
+{
+	if (index >= 0 and index < 4)
+	{
+		return points[index];
+	}
+	else
+	{
+		return ldraw::ColoredObject::getPoint(index);
+	}
+}