diff --git a/tutorial/t6.geo b/tutorial/t6.geo
index 2dfe57f2f943d9120b56ff07e46fdc83fd880192..b0eb0a19b8ea128ef6487bff05f481e411d36b28 100644
--- a/tutorial/t6.geo
+++ b/tutorial/t6.geo
@@ -27,7 +27,9 @@ Plane Surface(1) = {1};
 // Put 20 points with a refinement toward the extremities on curve 2
 Transfinite Line{2} = 20 Using Bump 0.05;
 
-// Put 20 points total on combination of curves l1, l2 and l3
+// Put 20 points total on combination of curves l1, l2 and l3 (beware
+// that the points p1 and p2 are shared by the curves, so we do not
+// create 6 + 6 + 10 = 22 points, but 20!)
 Transfinite Line{l1} = 6;
 Transfinite Line{l2} = 6;
 Transfinite Line{l3} = 10;
diff --git a/tutorial/t9.geo b/tutorial/t9.geo
index 46c045b8d7a29a7bf94a14c498a34488fed8794a..ea762ef24ca51dcfce2a3fbebb3f713e7c6e9184 100644
--- a/tutorial/t9.geo
+++ b/tutorial/t9.geo
@@ -24,7 +24,7 @@ Include "view3.pos" ;
 
 Plugin(Isosurface).Value = 0.67 ; // iso-value level
 Plugin(Isosurface).View = 0 ; // source view is View[0]
-Plugin(Isosurface).Run ; 
+Plugin(Isosurface).Run ; // run the plugin!
 
 // We also set some options for the `CutPlane' plugin (which computes
 // a section of a 3D view using the plane A*x+B*y+C*z+D=0), and then
@@ -50,6 +50,7 @@ Plugin(Annotate).FontSize = 28 ;
 Plugin(Annotate).Align = "Center" ; 
 Plugin(Annotate).View = 0 ;
 Plugin(Annotate).Run ; 
+
 Plugin(Annotate).Text = "(and a small subtitle)" ; 
 Plugin(Annotate).Y = 70 ; 
 Plugin(Annotate).Font = "Times-Roman" ;