diff --git a/scripts/pathdropcutter_test_2.py b/scripts/pathdropcutter_test_2.py
index e0f4611c..b589a731 100644
--- a/scripts/pathdropcutter_test_2.py
+++ b/scripts/pathdropcutter_test_2.py
@@ -95,8 +95,9 @@
     t_after = time.time()
     calctime = t_after-t_before
     print " done in ", calctime," s"
-    
     cl_filtered = f.getCLPoints()
+    print "       after filter we have", len(cl_filtered),"cl-points"
+    
     aclp_lifted2=[]
     for p in cl_filtered:
         p2 = ocl.Point(p.x,p.y,p.z) + ocl.Point(0,0,1)
diff --git a/scripts/tsp/tsp_01.py b/scripts/tsp/tsp_01.py
index fb638050..e364716b 100644
--- a/scripts/tsp/tsp_01.py
+++ b/scripts/tsp/tsp_01.py
@@ -6,6 +6,19 @@
 import math
 import gzip
 
+# Travelling Salesman Problem
+# a.k.a. drill-path optimization
+#
+# we have multiple points in the 2D plane to visit.
+# the task is to optimize the distance travelled by the tool while
+# visiting all points
+#
+# uses data from TSPLIB (not included in opencamlib)
+#
+# ocl.TSPSolver() is a wrapper for boost::metric_tsp_approx()
+# https://www.boost.org/doc/libs/1_67_0/libs/graph/doc/metric_tsp_approx.html
+
+
 def drawPoints(myscreen, pts):
     c=camvtk.PointCloud( pts ) 
     c.SetPoints()