diff --git a/app/Main.hs b/app/Main.hs
index 41c9798..eb3643b 100644
--- a/app/Main.hs
+++ b/app/Main.hs
@@ -101,7 +101,7 @@ testDocuments :: IntMap Document
 testDocuments = IntMap.fromList
   $ zip [0..]
     [ Document
-      { displayName    = "Document 1"
+      { displayName    = "Closed"
       , filePath       = Nothing
       , unsavedChanges = False
       , strokes        = [ Stroke ( ellipse 150 100 ( PointData Normal ( rect 30 6 $ BrushPointData Normal ) ) ) "Ellipse" True ( unsafeUnique 0 )
@@ -111,7 +111,7 @@ testDocuments = IntMap.fromList
       , zoomFactor     = 1
       }
     , Document
-      { displayName    = "Document 2"
+      { displayName    = "Line"
       , filePath       = Nothing
       , unsavedChanges = True
       , strokes        = [ Stroke linePts "Line" True ( unsafeUnique 1 ) ]
@@ -119,17 +119,32 @@ testDocuments = IntMap.fromList
       , viewportCenter = Point2D 0 0
       , zoomFactor     = 1
       }
+    , Document
+      { displayName    = "Short line"
+      , filePath       = Nothing
+      , unsavedChanges = False
+      , strokes        = [ Stroke linePts2 "ShortLine" True ( unsafeUnique 2 ) ]
+      , bounds         = AABB ( Point2D  0  0 ) ( Point2D 50 50 )
+      , viewportCenter = Point2D 0 0
+      , zoomFactor     = 1
+      }
     ]
   where
     linePts :: Seq ( StrokePoint PointData )
     linePts = Seq.fromList
-      [    PathPoint ( Point2D 0 (-100) ) ( PointData Normal ( ellipse 30 8 $ BrushPointData Normal ) )
-      , ControlPoint ( Point2D 0 ( -30) ) ( PointData Normal ( ellipse 25 6 $ BrushPointData Normal ) )
-      , ControlPoint ( Point2D 0 (  30) ) ( PointData Normal ( ellipse 15 6 $ BrushPointData Normal ) )
-      ,    PathPoint ( Point2D 0 ( 100) ) ( PointData Normal ( ellipse 15 6 $ BrushPointData Normal ) )
-      , ControlPoint ( Point2D 0 ( 150) ) ( PointData Normal ( ellipse 15 6 $ BrushPointData Normal ) )
-      , ControlPoint ( Point2D 0 ( 200) ) ( PointData Normal ( ellipse 15 6 $ BrushPointData Normal ) )
-      ,    PathPoint ( Point2D 0 ( 250) ) ( PointData Normal ( ellipse 10 1 $ BrushPointData Normal ) )
+      [    PathPoint ( Point2D 0 -100 ) ( PointData Normal ( ellipse 30 8 $ BrushPointData Normal ) )
+      , ControlPoint ( Point2D 0  -30 ) ( PointData Normal ( ellipse 25 6 $ BrushPointData Normal ) )
+      , ControlPoint ( Point2D 0   30 ) ( PointData Normal ( ellipse 15 6 $ BrushPointData Normal ) )
+      ,    PathPoint ( Point2D 0  100 ) ( PointData Normal ( ellipse 15 6 $ BrushPointData Normal ) )
+      , ControlPoint ( Point2D 0  150 ) ( PointData Normal ( ellipse 15 6 $ BrushPointData Normal ) )
+      , ControlPoint ( Point2D 0  200 ) ( PointData Normal ( ellipse 15 6 $ BrushPointData Normal ) )
+      ,    PathPoint ( Point2D 0  250 ) ( PointData Normal ( ellipse 10 1 $ BrushPointData Normal ) )
+      ]
+    linePts2 :: Seq ( StrokePoint PointData )
+    linePts2 = Seq.fromList
+      [    PathPoint ( Point2D 0 -100 ) ( PointData Normal ( ellipse  20 8 $ BrushPointData Normal ) )
+      --, ControlPoint ( Point2D 0    0 ) ( PointData Normal ( ellipse 140 8 $ BrushPointData Normal ) )
+      ,    PathPoint ( Point2D 0  100 ) ( PointData Normal ( ellipse  20 8 $ BrushPointData Normal ) )
       ]
 
 --------------------------------------------------------------------------------
diff --git a/src/lib/Math/Bezier/Stroke.hs b/src/lib/Math/Bezier/Stroke.hs
index dc79b7f..a854d22 100644
--- a/src/lib/Math/Bezier/Stroke.hs
+++ b/src/lib/Math/Bezier/Stroke.hs
@@ -44,7 +44,7 @@ import Data.Sequence
   ( Seq(..) )
 import qualified Data.Sequence as Seq
   ( splitAt, drop, dropWhileL
-  , zipWith3, zipWith4
+  , zipWith, zipWith3, zipWith4
   )
 
 -- generic-lens
@@ -275,7 +275,7 @@ stroke allPts@( spt0 :<| spt1 :<| spts )
             where
               s :: Double
               s = 1 - t
-      = ( fitCurve fwd, fitCurve bwd ) -- fitCurve bwd )
+      = ( fitCurve fwd, fitCurve bwd )
       <~> joinAndContinue tgt3 sp3 sps
     go p0 ps = error $ "stroke: unrecognised stroke type\n" <> show ( p0 :<| ps )
 
@@ -291,7 +291,7 @@ removePointData :: Seq ( StrokePoint d ) -> Seq ( StrokePoint () )
 removePointData = fmap ( set ( field @"pointData" ) () )
 
 lerpBrush :: forall d. Show d => Double -> Seq ( StrokePoint d ) -> Seq ( StrokePoint d ) -> Seq ( StrokePoint () )
-lerpBrush t p0s p1s = f <$> p0s <*> p1s
+lerpBrush t p0s p1s = Seq.zipWith f p0s p1s
   where
     f :: StrokePoint d -> StrokePoint d -> StrokePoint ()
     f ( PathPoint { coords = p0 } )