diff --git a/example/splinechart/splinewidget.cpp b/example/splinechart/splinewidget.cpp
index 83c06c4..c8a4347 100644
--- a/example/splinechart/splinewidget.cpp
+++ b/example/splinechart/splinewidget.cpp
@@ -27,10 +27,20 @@ SplineWidget::SplineWidget(QWidget *parent)
 //    series->add(QPointF(750, 180));
 //    series->add(QPointF(800, 170));
 
-    qsrand(time(NULL));
-    for (int i = 0; i < 100; i++)
+//    qsrand(time(NULL));
+//    for (int i = 0; i < 100; i++)
+//    {
+//        series->add(QPointF(i*7, qrand()%600));
+//    }
+    int k = 10;
+    for (int i = 0; i < 25; i++)
     {
-        series->add(QPointF(i*7, qrand()%600));
+        if (k > 60)
+        {
+            k = 10;
+        }
+        series->add(QPointF(i*50, k));
+        k +=10;
     }
 
     series->calculateControlPoints();
diff --git a/src/splinechart/qsplineseries.cpp b/src/splinechart/qsplineseries.cpp
index 15b1797..1091a58 100644
--- a/src/splinechart/qsplineseries.cpp
+++ b/src/splinechart/qsplineseries.cpp
@@ -55,7 +55,7 @@ void QSplineSeries::calculateControlPoints()
     rhs.append(m_x[0] + 2 * m_x[1]);
 
     // Set right hand side X values
-    for (int i = 1; i < m_x.size() - 1; ++i)
+    for (int i = 1; i < n - 1; ++i)
         rhs.append(4 * m_x[i] + 2 * m_x[i + 1]);
 
     rhs.append((8 * m_x[n - 1] + m_x[n]) / 2.0);
@@ -64,7 +64,7 @@ void QSplineSeries::calculateControlPoints()
     rhs[0] = m_y[0] + 2 * m_y[1];
 
     // Set right hand side Y values
-    for (int i = 1; i < m_y.size() - 1; ++i)
+    for (int i = 1; i < n - 1; ++i)
         rhs[i] = 4 * m_y[i] + 2 * m_y[i + 1];
 
     rhs[n - 1] = (8 * m_y[n - 1] + m_y[n]) / 2.0;
@@ -74,7 +74,7 @@ void QSplineSeries::calculateControlPoints()
     // Fill output arrays.
     //        firstControlPoints = new Point[n];
     //        secondControlPoints = new Point[n];
-    for (int i = 0; i < m_x.size(); ++i)
+    for (int i = 0; i < n; ++i)
     {
         // First control point
         m_controlPoints.append(QPointF(x[i], y[i]));