Add ring with a 6-nut shape

Ring_Nut.scad

@@ -0,0 +1,29 @@
+INNER_DIMENSION=19;
+HEIGHT=10;
+EDGES=6;
+FLATNESS=0.9;
+THICKNESS=8;
+
+$fn = 36;
+
+difference() {
+    union() {
+        translate([0, 0, HEIGHT/5])
+        rotate([180, 0])
+        linear_extrude(height=HEIGHT/5, scale=FLATNESS) {
+            circle(d=INNER_DIMENSION+THICKNESS, $fn=EDGES);
+        }
+        translate([0, 0, HEIGHT/5])
+        linear_extrude(height=HEIGHT*3/5) {
+            circle(d=INNER_DIMENSION+THICKNESS, $fn=EDGES);
+        }
+        translate([0, 0, HEIGHT*4/5])
+        linear_extrude(height=HEIGHT/5, scale=FLATNESS) {
+            circle(d=INNER_DIMENSION+THICKNESS, $fn=EDGES);
+        }
+    }
+    
+    linear_extrude(height=HEIGHT) {
+        circle(d=INNER_DIMENSION);
+    }
+}