diff --git a/src/bin/render_lines_gui.rs b/src/bin/render_lines_gui.rs
index 310ed4a..3b1e117 100644
--- a/src/bin/render_lines_gui.rs
+++ b/src/bin/render_lines_gui.rs
@@ -890,9 +890,9 @@ fn view_line_canvas(app: &App, model: &GuiModel, frame: Frame) {
 
     // show each configured laser in the canvas. Highlight the selected.
     for (dac_id, config) in model.per_laser_config.iter() {
-        let rect = shape_rect(LaserSpace::READY);
+        let rect = shape_rect(LaserSpace::READY, 11);
         let points = config.filters.reverse(&rect);
-
+        
         
         
         let vertices = points.points.iter().map(|p| {
@@ -910,9 +910,24 @@ fn view_line_canvas(app: &App, model: &GuiModel, frame: Frame) {
         });
     
         draw.polyline()
-            .weight(thickness)
-            .join_round()
-            .points_colored(vertices);
+        .weight(thickness)
+        .join_round()
+        .points_colored(vertices);
+
+        // draggable corners for the selected area
+        if model.selected_stream == Some(dac_id.clone()){
+            let rect = shape_rect(LaserSpace::READY, 1); // find corners
+            let points = config.filters.reverse(&rect);
+            for p in points.points {
+                let pos = [p.position[0] * scale + translate_x, p.position[1] * -scale + translate_y];
+
+                draw.ellipse()
+                    .x_y(pos[0], pos[1])
+                    .radius(3.)
+                    .color(srgba(229./255.,45./255.,159./255.,0.8));
+                
+            }
+        }
     }
     
 
diff --git a/src/trap/laser.rs b/src/trap/laser.rs
index a830062..c769345 100644
--- a/src/trap/laser.rs
+++ b/src/trap/laser.rs
@@ -169,36 +169,36 @@ pub  enum LaserSpace {
     READY,
 }
 
-pub fn shape_rect(space: LaserSpace) -> LaserPoints {
+pub fn shape_rect(space: LaserSpace, steps: usize) -> LaserPoints {
     let offset: f32 = match space { LaserSpace::OLD =>  0., _ => 1. };
     let factor: f32 = match space { LaserSpace::OLD =>  1., _ => 2./0xFFF as f32 };
     let mut points = Vec::new();
-    let steps: usize = 10;
+    // let steps: usize = 10;
     for i in (0..=steps).rev() {
         points.push(laser::Point{
             position:[0xFFF as f32 * factor - offset, (0xFFF * i / steps) as f32 * factor - offset],
-            color: [1.,1.,1.],
+            color: [0.2,0.2,0.2],
             weight: 0,
         });
     }
-    for i in (0..=steps).rev() {
+    for i in (0..steps).rev() {
         points.push(laser::Point{
             position:[(0xFFF * i / steps)  as f32 * factor - offset, 0.0 * factor - offset],
-            color: [1.,1.,1.],
+            color: [0.2,0.2,0.2],
             weight: 0,
         });
     }
-    for i in 0..=steps {
+    for i in 0..steps {
         points.push(laser::Point{
             position:[0.0  * factor - offset, (0xFFF * i / steps) as f32 * factor - offset],
-            color: [1.,1.,1.],
+            color: [0.2,0.2,0.2],
             weight: 0,
         });
     }
     for i in 0..=steps {
         points.push(laser::Point{
             position:[(0xFFF * i / steps) as f32 * factor - offset , 0xFFF as f32 * factor - offset],
-            color: [1.,1.,1.],
+            color: [0.2,0.2,0.2],
             weight: 0,
         });
     }
@@ -212,17 +212,18 @@ impl StreamSource{
         match self {
             Self::CurrentLines => current_lines,
             Self::Rectangle => {
-                shape_rect(LaserSpace::OLD)
+                shape_rect(LaserSpace::READY, 11)
             },
             Self::Grid => {
                 let lines: usize = 5;
+                let half = (0xFFF / 2) as f32;
                 let mut points = Vec::new();
                 // vertical lines
                 for i in 0..=lines {
                     let offset = if i % 2 == 0 { 0 } else {0xFFF } as f32; 
                     let x = i * 0xFFF / lines;
                     points.push(laser::Point{
-                        position:[x as f32, offset],
+                        position:[(x as f32 - half) / half, (offset as f32 - half)/half],
                         color: [0., 0., 0.],
                         weight: 0,
                     });
@@ -230,7 +231,7 @@ impl StreamSource{
                         // go back and forth, so galvo has it easier
                         let y = if i % 2 == 0 { j } else {0xFFF - j}; 
                         points.push(laser::Point{
-                            position:[x as f32, y as f32],
+                            position:[(x as f32 - half)/half, (y as f32 - half)/half],
                             color: [1.,1.,1.],
                             weight: 0,
                         });
@@ -242,7 +243,7 @@ impl StreamSource{
                     let offset = if i % 2 == 0 { 0 } else {0xFFF } as f32; 
                     let y =  i * 0xFFF / lines;
                     points.push(laser::Point{
-                        position:[offset, y as f32],
+                        position:[(offset as f32 - half)/half, (y as f32 - half)/half],
                         color: [0., 0., 0.],
                         weight: 0,
                     });
@@ -250,7 +251,7 @@ impl StreamSource{
                         // go back and forth, so galvo has it easier
                         let x = if i % 2 == 0 { j } else {0xFFF - j}; 
                         points.push(laser::Point{
-                            position:[x as f32, y as f32],
+                            position:[(x as f32 - half)/half, (y as f32 - half)/half],
                             color: [1.,1.,1.],
                             weight: 0,
                         });