diff --git a/sirius.cpp b/sirius.cpp
index 086fb17085fd888e3f077594b30cb8d28dd16e62..95f496b9fe95192a671e24d6cfcc3cfe4de62c58 100644
--- a/sirius.cpp
+++ b/sirius.cpp
@@ -231,8 +231,8 @@ class Triangulated : public Drawable {
     bool checkPotDiag(std::vector<vec2>::iterator currVertex) {
         vec2 currPotDiag1 = *getNextVertex(currVertex);
         vec2 currPotDiag2 = *getPreviousVertex(currVertex);
-        for (auto currEdgeStart = getNextVertex(currVertex);
-             currEdgeStart != getPreviousVertex(currVertex);
+        for (auto currEdgeStart = getNextVertex(getNextVertex(currVertex));
+             currEdgeStart != getPreviousVertex(getPreviousVertex(currVertex));
              currEdgeStart = getNextVertex(currEdgeStart)
                 )
             if (intersectEachOther(*currEdgeStart, *getNextVertex(currEdgeStart),