diff --git a/lib/bounding-box.ts b/lib/bounding-box.ts
index 1195edb..5553e26 100644
--- a/lib/bounding-box.ts
+++ b/lib/bounding-box.ts
@@ -28,7 +28,7 @@ export function getBoundingBoxCenter(bbox: Bbox): Point {
   };
 }
 
-function dilateBoundingBox(bbox: Bbox, amount: number): Bbox {
+export function dilateBoundingBox(bbox: Bbox, amount: number): Bbox {
   return {
     minX: bbox.minX - amount,
     maxX: bbox.maxX + amount,
diff --git a/lib/browser-main.tsx b/lib/browser-main.tsx
index f641925..9cdf388 100644
--- a/lib/browser-main.tsx
+++ b/lib/browser-main.tsx
@@ -1,7 +1,10 @@
 import React, { useState } from "react";
 import ReactDOM from "react-dom";
-import { getBoundingBoxSize } from "./bounding-box";
+import { Point } from "../vendor/bezier-js";
+import { Bbox, dilateBoundingBox, getBoundingBoxSize } from "./bounding-box";
 import { FILL_REPLACEMENT_COLOR, STROKE_REPLACEMENT_COLOR } from "./colors";
+import * as colors from "./colors";
+import { Specs } from "./specs";
 
 import _SvgVocabulary from "./svg-vocabulary.json";
 import type { SvgSymbolData, SvgSymbolElement } from "./vocabulary";
@@ -19,6 +22,7 @@ if (!appEl) {
 type SvgSymbolContext = {
   stroke: string;
   fill: string;
+  showSpecs: boolean;
 };
 
 type SvgSymbolProps = {
@@ -56,19 +60,101 @@ function reactifySvgSymbolElement(
   );
 }
 
+const ATTACHMENT_POINT_RADIUS = 20;
+
+const AttachmentPoints: React.FC<{ color: string; points: Point[] }> = (
+  props
+) => (
+  <>
+    {props.points.map((p, i) => (
+      <circle
+        key={i}
+        fill={props.color}
+        r={ATTACHMENT_POINT_RADIUS}
+        cx={p.x}
+        cy={p.y}
+      />
+    ))}
+  </>
+);
+
+const BoundingBoxes: React.FC<{ fill: string; bboxes: Bbox[] }> = (props) => (
+  <>
+    {props.bboxes.map((b, i) => {
+      const [width, height] = getBoundingBoxSize(b);
+      return (
+        <rect
+          key={i}
+          x={b.minX}
+          y={b.minY}
+          width={width}
+          height={height}
+          fill={props.fill}
+        />
+      );
+    })}
+  </>
+);
+
+const SvgSymbolSpecs: React.FC<{ specs: Specs }> = ({ specs }) => {
+  return (
+    <>
+      {specs.tail && (
+        <AttachmentPoints
+          color={colors.TAIL_ATTACHMENT_COLOR}
+          points={specs.tail}
+        />
+      )}
+      {specs.leg && (
+        <AttachmentPoints
+          color={colors.LEG_ATTACHMENT_COLOR}
+          points={specs.leg}
+        />
+      )}
+      {specs.arm && (
+        <AttachmentPoints
+          color={colors.ARM_ATTACHMENT_COLOR}
+          points={specs.arm}
+        />
+      )}
+      {specs.horn && (
+        <AttachmentPoints
+          color={colors.HORN_ATTACHMENT_COLOR}
+          points={specs.horn}
+        />
+      )}
+      {specs.crown && (
+        <AttachmentPoints
+          color={colors.CROWN_ATTACHMENT_COLOR}
+          points={specs.crown}
+        />
+      )}
+      {specs.nesting && (
+        <BoundingBoxes
+          fill={colors.NESTING_BOUNDING_BOX_COLOR}
+          bboxes={specs.nesting}
+        />
+      )}
+    </>
+  );
+};
+
+const BBOX_DILATION = 50;
+
 const SvgSymbol: React.FC<SvgSymbolProps> = (props) => {
   const d = props.data;
+  const bbox = dilateBoundingBox(d.bbox, BBOX_DILATION);
   const scale = props.scale || 1;
-  const [width, height] = getBoundingBoxSize(d.bbox);
+  const [width, height] = getBoundingBoxSize(bbox);
 
   return (
     <svg
-      viewBox={`${d.bbox.minX} ${d.bbox.minY} ${width} ${height}`}
+      viewBox={`${bbox.minX} ${bbox.minY} ${width} ${height}`}
       width={px(width * scale)}
       height={px(height * scale)}
-      style={{ margin: "10px" }}
     >
       {props.data.layers.map(reactifySvgSymbolElement.bind(null, props))}
+      {props.showSpecs && d.specs && <SvgSymbolSpecs specs={d.specs} />}
     </svg>
   );
 };
@@ -76,6 +162,7 @@ const SvgSymbol: React.FC<SvgSymbolProps> = (props) => {
 const App: React.FC<{}> = () => {
   const [stroke, setStroke] = useState("#000000");
   const [fill, setFill] = useState("#ffffff");
+  const [showSpecs, setShowSpecs] = useState(false);
 
   return (
     <>
@@ -94,7 +181,15 @@ const App: React.FC<{}> = () => {
           value={fill}
           onChange={(e) => setFill(e.target.value)}
           id="fill"
-        />
+        />{" "}
+        <label>
+          <input
+            type="checkbox"
+            checked={showSpecs}
+            onChange={(e) => setShowSpecs(e.target.checked)}
+          />{" "}
+          Show specs
+        </label>
       </p>
       {SvgVocabulary.map((symbolData) => (
         <div
@@ -120,6 +215,7 @@ const App: React.FC<{}> = () => {
               scale={0.25}
               stroke={stroke}
               fill={fill}
+              showSpecs={showSpecs}
             />
           </div>
         </div>