diff --git a/2d/dice-tower/dice-tower.scad b/2d/dice-tower/dice-tower.scad
index 524df95..dc35b3e 100644
--- a/2d/dice-tower/dice-tower.scad
+++ b/2d/dice-tower/dice-tower.scad
@@ -9,6 +9,8 @@ outer_height = outer_depth * golden_ratio;
 
 inc_top = false;
 
+hole_diameter = 4.1;
+
 module barrier_A() {
    panel("A", outer_width, outer_depth*0.5, 0, 1, 0, 1, margin=5);
 }
@@ -31,6 +33,7 @@ module left_side() {
       translate([-0.7*inch, 1.85*inch,0]) rotate([0,0,-25]) holes(1, outer_depth*0.5 - 10);
       translate([ 0.8*inch, 0.10*inch,0]) rotate([0,0, 30]) holes(1, outer_depth*0.4 - 10);
       translate([-0.3*inch,-1.80*inch,0]) rotate([0,0,-25]) holes(1, outer_depth*0.7 - 10);
+      translate([-(thickness + (20+thickness/2)/sqrt(2) - outer_depth/2), -(outer_height - 40 - thickness)/2], 0) square([sqrt(pow(hole_diameter,2) - pow(thickness,2)), thickness], center=true);
    }
 }
 
@@ -44,6 +47,7 @@ module right_side() {
       translate([ 0.7*inch, 1.85*inch,0]) rotate([0,0, 25]) holes(1, outer_depth*0.5 - 10);
       translate([-0.8*inch, 0.10*inch,0]) rotate([0,0,-30]) holes(1, outer_depth*0.4 - 10);
       translate([ 0.3*inch,-1.80*inch,0]) rotate([0,0, 25]) holes(1, outer_depth*0.7 - 10);
+      translate([(thickness + (20+thickness/2)/sqrt(2) - outer_depth/2), -(outer_height - 40 - thickness)/2], 0) square([sqrt(pow(hole_diameter,2) - pow(thickness,2)), thickness], center=true);
    }
 }
 
@@ -64,8 +68,11 @@ module bottom_side() {
 
 module extra_layout() {
    translate([0, -(outer_height/2 + spacing + outer_width/2), 0]) {
-      translate([-(outer_width/2 + spacing + outer_depth + spacing + outer_width/2), 0, 0])
+      translate([-(outer_width/2 + spacing + outer_depth + spacing + outer_width/2), -5, 0]) {
          barrier_A();
+         translate([-thickness,26,0]) square([sqrt(pow(hole_diameter,2) - pow(thickness,2)), 2.05*thickness], center=true);
+         translate([ thickness,26,0]) square([sqrt(pow(hole_diameter,2) - pow(thickness,2)), 2.05*thickness], center=true);
+      }
       translate([0, 48, 0]) barrier_B();
       //translate([outer_width/2 + spacing + outer_depth/2, 0, 0])
       translate([4, 0, 0])
@@ -80,4 +87,9 @@ module extra_assembly() {
    translate([0, 0.3*inch,-1.80*inch]) rotate([ 25,0,0]) thicken() barrier_C();
    %translate([0,-10,20]) rotate([-30,45,0]) cube([19.5,19.5,19.5], center=true);
    %translate([0,20,-15]) rotate([ 60,76,0]) cube([19.5,19.5,19.5], center=true);
+   %translate([outer_width/2,
+   thickness + (20+thickness/2)/sqrt(2) - outer_depth/2,
+   -(outer_height - 40 - thickness)/2]) {
+      sphere(hole_diameter/2);
+   }
 }