diff --git a/Oliwka/na_kamyczki.scad b/Oliwka/na_kamyczki.scad
index 8999f9b..3940bd1 100644
--- a/Oliwka/na_kamyczki.scad
+++ b/Oliwka/na_kamyczki.scad
@@ -8,6 +8,9 @@ height_up = 15;
 wall_thickness = 2;
 shelf_thickness = 1;
 
+// space left - ile od krawędzi wyciąć środek
+sl = 20;
+
 include <BOSL2/std.scad>
 include <BOSL2/shapes3d.scad>
 
@@ -26,6 +29,8 @@ total_height = height_up + height_down + shelf_thickness;
    translate([width/2, length/2, height_up])
    translate([wt,wt,height_down + st + 0.1])
     cuboid([width, length, height_up * 2], rounding=10);
+   translate([sl, sl,0])
+     cube([width - sl*2, length - sl*2, total_height*2]);
 }