diff --git a/lab2/ibspline.py b/lab2/ibspline.py
index ec23470..7c88030 100644
--- a/lab2/ibspline.py
+++ b/lab2/ibspline.py
@@ -76,8 +76,8 @@ def ibspline(inputA, inputB=None):
             elif i >= h + 1:
                 new_points.append(points[i - 1])
             else:
-                denom = knot_vector[i+n] - knot_vector[i]
-                alpha = (t_hat - knot_vector[i]) / denom if denom > 1e-8 else 0.0
+                denom = knot_vector[i+n-1] - knot_vector[i-1]
+                alpha = (t_hat - knot_vector[i-1]) / denom if denom > 1e-8 else 0.0
                 px = (1 - alpha) * points[i-1][0] + alpha * points[i][0]
                 py = (1 - alpha) * points[i-1][1] + alpha * points[i][1]
                 new_points.append((px, py))
@@ -87,7 +87,7 @@ def ibspline(inputA, inputB=None):
         vY = [p[1] for p in new_points]
         
         # Update knot vector: insert t_hat
-        knot_vector.insert(h + 1, t_hat)
+        knot_vector.insert(h, t_hat)
         
         outputPlotMessage(f"Added Control Point. (m={len(vX)})")
         redrawPlot(vX, vY)
@@ -337,18 +337,6 @@ def ibspline(inputA, inputB=None):
                 enableButtons()
         return
 
-    # Pick and move a vertex
-    def pickPointCallback(event):
-        global iv_selected, cid_moveCallback
-
-        if (len(event.ind) < 1): return
-
-        if (event.ind[0] >= 0) and (event.ind[0] < len(vX)):
-            iv_selected = event.ind[0]
-            cid_moveCallback = \
-                fig.canvas.mpl_connect('button_release_event', moveVertexCallback)
-
-        return
 
     # Move selected vertex to location (event.xdata, event.ydata)
     def moveVertexCallback(event):