diff --git a/dist/extension.zip b/dist/extension.zip
index 36f7010..e463bc2 100644
Binary files a/dist/extension.zip and b/dist/extension.zip differ
diff --git a/dist/extension/birb.js b/dist/extension/birb.js
index d1df198..1b60e97 100644
--- a/dist/extension/birb.js
+++ b/dist/extension/birb.js
@@ -226,6 +226,22 @@
 		return document.documentElement.clientHeight;
 	}
 
+	const TAG = {
+		DEFAULT: "default",
+		TUFT: "tuft",
+	};
+
+	class Layer {
+		/**
+		 * @param {string[][]} pixels
+		 * @param {string} [tag]
+		 */
+		constructor(pixels, tag = TAG.DEFAULT) {
+			this.pixels = pixels;
+			this.tag = tag;
+		}
+	}
+
 	/**
 	 * Palette color names
 	 * @type {Record<string, string>}
@@ -333,7 +349,7 @@
 			[PALETTE.UNDERBELLY]: "#d7cfcb",
 			[PALETTE.WING]: "#b1b5c5",
 			[PALETTE.WING_EDGE]: "#9d9fa9",
-		}, ["tuft"]),
+		}, [TAG.TUFT]),
 		europeanRobin: new BirdType("European Robin",
 			"Native to western Europe, this is the quintessential robin. Quite friendly, you'll often find them searching for worms.", {
 			[PALETTE.FOOT]: "#af8e75",
@@ -355,7 +371,7 @@
 			[PALETTE.UNDERBELLY]: "#dc3719",
 			[PALETTE.WING]: "#d23215",
 			[PALETTE.WING_EDGE]: "#b1321c",
-		}, ["tuft"]),
+		}, [TAG.TUFT]),
 		americanGoldfinch: new BirdType("American Goldfinch",
 			"Coloured a brilliant yellow, this bird feeds almost entirely on the seeds of plants such as thistle, sunflowers, and coneflowers.", {
 			[PALETTE.BEAK]: "#ffaf34",
@@ -432,17 +448,6 @@
 		}),
 	};
 
-	class Layer {
-		/**
-		 * @param {string[][]} pixels
-		 * @param {string} [tag]
-		 */
-		constructor(pixels, tag = "default") {
-			this.pixels = pixels;
-			this.tag = tag;
-		}
-	}
-
 	class Frame {
 
 		/** @type {{ [tag: string]: string[][] }} */
@@ -457,10 +462,10 @@
 			for (let layer of layers) {
 				tags.add(layer.tag);
 			}
-			tags.add("default");
+			tags.add(TAG.DEFAULT);
 			for (let tag of tags) {
 				let maxHeight = layers.reduce((max, layer) => Math.max(max, layer.pixels.length), 0);
-				if (layers[0].tag !== "default") {
+				if (layers[0].tag !== TAG.DEFAULT) {
 					throw new Error("First layer must have the 'default' tag");
 				}
 				this.pixels = layers[0].pixels.map(row => row.slice());
@@ -470,7 +475,7 @@
 				}
 				// Combine layers
 				for (let i = 1; i < layers.length; i++) {
-					if (layers[i].tag === "default" || layers[i].tag === tag) {
+					if (layers[i].tag === TAG.DEFAULT || layers[i].tag === tag) {
 						let layerPixels = layers[i].pixels;
 						let topMargin = maxHeight - layerPixels.length;
 						for (let y = 0; y < layerPixels.length; y++) {
@@ -488,8 +493,8 @@
 		 * @param {string} [tag]
 		 * @returns {string[][]}
 		 */
-		getPixels(tag = "default") {
-			return this.#pixelsByTag[tag] ?? this.#pixelsByTag["default"];
+		getPixels(tag = TAG.DEFAULT) {
+			return this.#pixelsByTag[tag] ?? this.#pixelsByTag[TAG.DEFAULT];
 		}
 
 		/**
diff --git a/dist/obsidian/main.js b/dist/obsidian/main.js
index 255ba72..e847f07 100644
--- a/dist/obsidian/main.js
+++ b/dist/obsidian/main.js
@@ -231,6 +231,22 @@ module.exports = class PocketBird extends Plugin {
 		return document.documentElement.clientHeight;
 	}
 
+	const TAG = {
+		DEFAULT: "default",
+		TUFT: "tuft",
+	};
+
+	class Layer {
+		/**
+		 * @param {string[][]} pixels
+		 * @param {string} [tag]
+		 */
+		constructor(pixels, tag = TAG.DEFAULT) {
+			this.pixels = pixels;
+			this.tag = tag;
+		}
+	}
+
 	/**
 	 * Palette color names
 	 * @type {Record<string, string>}
@@ -338,7 +354,7 @@ module.exports = class PocketBird extends Plugin {
 			[PALETTE.UNDERBELLY]: "#d7cfcb",
 			[PALETTE.WING]: "#b1b5c5",
 			[PALETTE.WING_EDGE]: "#9d9fa9",
-		}, ["tuft"]),
+		}, [TAG.TUFT]),
 		europeanRobin: new BirdType("European Robin",
 			"Native to western Europe, this is the quintessential robin. Quite friendly, you'll often find them searching for worms.", {
 			[PALETTE.FOOT]: "#af8e75",
@@ -360,7 +376,7 @@ module.exports = class PocketBird extends Plugin {
 			[PALETTE.UNDERBELLY]: "#dc3719",
 			[PALETTE.WING]: "#d23215",
 			[PALETTE.WING_EDGE]: "#b1321c",
-		}, ["tuft"]),
+		}, [TAG.TUFT]),
 		americanGoldfinch: new BirdType("American Goldfinch",
 			"Coloured a brilliant yellow, this bird feeds almost entirely on the seeds of plants such as thistle, sunflowers, and coneflowers.", {
 			[PALETTE.BEAK]: "#ffaf34",
@@ -437,17 +453,6 @@ module.exports = class PocketBird extends Plugin {
 		}),
 	};
 
-	class Layer {
-		/**
-		 * @param {string[][]} pixels
-		 * @param {string} [tag]
-		 */
-		constructor(pixels, tag = "default") {
-			this.pixels = pixels;
-			this.tag = tag;
-		}
-	}
-
 	class Frame {
 
 		/** @type {{ [tag: string]: string[][] }} */
@@ -462,10 +467,10 @@ module.exports = class PocketBird extends Plugin {
 			for (let layer of layers) {
 				tags.add(layer.tag);
 			}
-			tags.add("default");
+			tags.add(TAG.DEFAULT);
 			for (let tag of tags) {
 				let maxHeight = layers.reduce((max, layer) => Math.max(max, layer.pixels.length), 0);
-				if (layers[0].tag !== "default") {
+				if (layers[0].tag !== TAG.DEFAULT) {
 					throw new Error("First layer must have the 'default' tag");
 				}
 				this.pixels = layers[0].pixels.map(row => row.slice());
@@ -475,7 +480,7 @@ module.exports = class PocketBird extends Plugin {
 				}
 				// Combine layers
 				for (let i = 1; i < layers.length; i++) {
-					if (layers[i].tag === "default" || layers[i].tag === tag) {
+					if (layers[i].tag === TAG.DEFAULT || layers[i].tag === tag) {
 						let layerPixels = layers[i].pixels;
 						let topMargin = maxHeight - layerPixels.length;
 						for (let y = 0; y < layerPixels.length; y++) {
@@ -493,8 +498,8 @@ module.exports = class PocketBird extends Plugin {
 		 * @param {string} [tag]
 		 * @returns {string[][]}
 		 */
-		getPixels(tag = "default") {
-			return this.#pixelsByTag[tag] ?? this.#pixelsByTag["default"];
+		getPixels(tag = TAG.DEFAULT) {
+			return this.#pixelsByTag[tag] ?? this.#pixelsByTag[TAG.DEFAULT];
 		}
 
 		/**
diff --git a/dist/userscript/birb.user.js b/dist/userscript/birb.user.js
index 01018f5..c794adb 100644
--- a/dist/userscript/birb.user.js
+++ b/dist/userscript/birb.user.js
@@ -240,6 +240,22 @@
 		return document.documentElement.clientHeight;
 	}
 
+	const TAG = {
+		DEFAULT: "default",
+		TUFT: "tuft",
+	};
+
+	class Layer {
+		/**
+		 * @param {string[][]} pixels
+		 * @param {string} [tag]
+		 */
+		constructor(pixels, tag = TAG.DEFAULT) {
+			this.pixels = pixels;
+			this.tag = tag;
+		}
+	}
+
 	/**
 	 * Palette color names
 	 * @type {Record<string, string>}
@@ -347,7 +363,7 @@
 			[PALETTE.UNDERBELLY]: "#d7cfcb",
 			[PALETTE.WING]: "#b1b5c5",
 			[PALETTE.WING_EDGE]: "#9d9fa9",
-		}, ["tuft"]),
+		}, [TAG.TUFT]),
 		europeanRobin: new BirdType("European Robin",
 			"Native to western Europe, this is the quintessential robin. Quite friendly, you'll often find them searching for worms.", {
 			[PALETTE.FOOT]: "#af8e75",
@@ -369,7 +385,7 @@
 			[PALETTE.UNDERBELLY]: "#dc3719",
 			[PALETTE.WING]: "#d23215",
 			[PALETTE.WING_EDGE]: "#b1321c",
-		}, ["tuft"]),
+		}, [TAG.TUFT]),
 		americanGoldfinch: new BirdType("American Goldfinch",
 			"Coloured a brilliant yellow, this bird feeds almost entirely on the seeds of plants such as thistle, sunflowers, and coneflowers.", {
 			[PALETTE.BEAK]: "#ffaf34",
@@ -446,17 +462,6 @@
 		}),
 	};
 
-	class Layer {
-		/**
-		 * @param {string[][]} pixels
-		 * @param {string} [tag]
-		 */
-		constructor(pixels, tag = "default") {
-			this.pixels = pixels;
-			this.tag = tag;
-		}
-	}
-
 	class Frame {
 
 		/** @type {{ [tag: string]: string[][] }} */
@@ -471,10 +476,10 @@
 			for (let layer of layers) {
 				tags.add(layer.tag);
 			}
-			tags.add("default");
+			tags.add(TAG.DEFAULT);
 			for (let tag of tags) {
 				let maxHeight = layers.reduce((max, layer) => Math.max(max, layer.pixels.length), 0);
-				if (layers[0].tag !== "default") {
+				if (layers[0].tag !== TAG.DEFAULT) {
 					throw new Error("First layer must have the 'default' tag");
 				}
 				this.pixels = layers[0].pixels.map(row => row.slice());
@@ -484,7 +489,7 @@
 				}
 				// Combine layers
 				for (let i = 1; i < layers.length; i++) {
-					if (layers[i].tag === "default" || layers[i].tag === tag) {
+					if (layers[i].tag === TAG.DEFAULT || layers[i].tag === tag) {
 						let layerPixels = layers[i].pixels;
 						let topMargin = maxHeight - layerPixels.length;
 						for (let y = 0; y < layerPixels.length; y++) {
@@ -502,8 +507,8 @@
 		 * @param {string} [tag]
 		 * @returns {string[][]}
 		 */
-		getPixels(tag = "default") {
-			return this.#pixelsByTag[tag] ?? this.#pixelsByTag["default"];
+		getPixels(tag = TAG.DEFAULT) {
+			return this.#pixelsByTag[tag] ?? this.#pixelsByTag[TAG.DEFAULT];
 		}
 
 		/**
diff --git a/dist/web/birb.embed.js b/dist/web/birb.embed.js
index 722645a..0d3bcb5 100644
--- a/dist/web/birb.embed.js
+++ b/dist/web/birb.embed.js
@@ -226,6 +226,22 @@
 		return document.documentElement.clientHeight;
 	}
 
+	const TAG = {
+		DEFAULT: "default",
+		TUFT: "tuft",
+	};
+
+	class Layer {
+		/**
+		 * @param {string[][]} pixels
+		 * @param {string} [tag]
+		 */
+		constructor(pixels, tag = TAG.DEFAULT) {
+			this.pixels = pixels;
+			this.tag = tag;
+		}
+	}
+
 	/**
 	 * Palette color names
 	 * @type {Record<string, string>}
@@ -333,7 +349,7 @@
 			[PALETTE.UNDERBELLY]: "#d7cfcb",
 			[PALETTE.WING]: "#b1b5c5",
 			[PALETTE.WING_EDGE]: "#9d9fa9",
-		}, ["tuft"]),
+		}, [TAG.TUFT]),
 		europeanRobin: new BirdType("European Robin",
 			"Native to western Europe, this is the quintessential robin. Quite friendly, you'll often find them searching for worms.", {
 			[PALETTE.FOOT]: "#af8e75",
@@ -355,7 +371,7 @@
 			[PALETTE.UNDERBELLY]: "#dc3719",
 			[PALETTE.WING]: "#d23215",
 			[PALETTE.WING_EDGE]: "#b1321c",
-		}, ["tuft"]),
+		}, [TAG.TUFT]),
 		americanGoldfinch: new BirdType("American Goldfinch",
 			"Coloured a brilliant yellow, this bird feeds almost entirely on the seeds of plants such as thistle, sunflowers, and coneflowers.", {
 			[PALETTE.BEAK]: "#ffaf34",
@@ -432,17 +448,6 @@
 		}),
 	};
 
-	class Layer {
-		/**
-		 * @param {string[][]} pixels
-		 * @param {string} [tag]
-		 */
-		constructor(pixels, tag = "default") {
-			this.pixels = pixels;
-			this.tag = tag;
-		}
-	}
-
 	class Frame {
 
 		/** @type {{ [tag: string]: string[][] }} */
@@ -457,10 +462,10 @@
 			for (let layer of layers) {
 				tags.add(layer.tag);
 			}
-			tags.add("default");
+			tags.add(TAG.DEFAULT);
 			for (let tag of tags) {
 				let maxHeight = layers.reduce((max, layer) => Math.max(max, layer.pixels.length), 0);
-				if (layers[0].tag !== "default") {
+				if (layers[0].tag !== TAG.DEFAULT) {
 					throw new Error("First layer must have the 'default' tag");
 				}
 				this.pixels = layers[0].pixels.map(row => row.slice());
@@ -470,7 +475,7 @@
 				}
 				// Combine layers
 				for (let i = 1; i < layers.length; i++) {
-					if (layers[i].tag === "default" || layers[i].tag === tag) {
+					if (layers[i].tag === TAG.DEFAULT || layers[i].tag === tag) {
 						let layerPixels = layers[i].pixels;
 						let topMargin = maxHeight - layerPixels.length;
 						for (let y = 0; y < layerPixels.length; y++) {
@@ -488,8 +493,8 @@
 		 * @param {string} [tag]
 		 * @returns {string[][]}
 		 */
-		getPixels(tag = "default") {
-			return this.#pixelsByTag[tag] ?? this.#pixelsByTag["default"];
+		getPixels(tag = TAG.DEFAULT) {
+			return this.#pixelsByTag[tag] ?? this.#pixelsByTag[TAG.DEFAULT];
 		}
 
 		/**
diff --git a/dist/web/birb.js b/dist/web/birb.js
index 722645a..0d3bcb5 100644
--- a/dist/web/birb.js
+++ b/dist/web/birb.js
@@ -226,6 +226,22 @@
 		return document.documentElement.clientHeight;
 	}
 
+	const TAG = {
+		DEFAULT: "default",
+		TUFT: "tuft",
+	};
+
+	class Layer {
+		/**
+		 * @param {string[][]} pixels
+		 * @param {string} [tag]
+		 */
+		constructor(pixels, tag = TAG.DEFAULT) {
+			this.pixels = pixels;
+			this.tag = tag;
+		}
+	}
+
 	/**
 	 * Palette color names
 	 * @type {Record<string, string>}
@@ -333,7 +349,7 @@
 			[PALETTE.UNDERBELLY]: "#d7cfcb",
 			[PALETTE.WING]: "#b1b5c5",
 			[PALETTE.WING_EDGE]: "#9d9fa9",
-		}, ["tuft"]),
+		}, [TAG.TUFT]),
 		europeanRobin: new BirdType("European Robin",
 			"Native to western Europe, this is the quintessential robin. Quite friendly, you'll often find them searching for worms.", {
 			[PALETTE.FOOT]: "#af8e75",
@@ -355,7 +371,7 @@
 			[PALETTE.UNDERBELLY]: "#dc3719",
 			[PALETTE.WING]: "#d23215",
 			[PALETTE.WING_EDGE]: "#b1321c",
-		}, ["tuft"]),
+		}, [TAG.TUFT]),
 		americanGoldfinch: new BirdType("American Goldfinch",
 			"Coloured a brilliant yellow, this bird feeds almost entirely on the seeds of plants such as thistle, sunflowers, and coneflowers.", {
 			[PALETTE.BEAK]: "#ffaf34",
@@ -432,17 +448,6 @@
 		}),
 	};
 
-	class Layer {
-		/**
-		 * @param {string[][]} pixels
-		 * @param {string} [tag]
-		 */
-		constructor(pixels, tag = "default") {
-			this.pixels = pixels;
-			this.tag = tag;
-		}
-	}
-
 	class Frame {
 
 		/** @type {{ [tag: string]: string[][] }} */
@@ -457,10 +462,10 @@
 			for (let layer of layers) {
 				tags.add(layer.tag);
 			}
-			tags.add("default");
+			tags.add(TAG.DEFAULT);
 			for (let tag of tags) {
 				let maxHeight = layers.reduce((max, layer) => Math.max(max, layer.pixels.length), 0);
-				if (layers[0].tag !== "default") {
+				if (layers[0].tag !== TAG.DEFAULT) {
 					throw new Error("First layer must have the 'default' tag");
 				}
 				this.pixels = layers[0].pixels.map(row => row.slice());
@@ -470,7 +475,7 @@
 				}
 				// Combine layers
 				for (let i = 1; i < layers.length; i++) {
-					if (layers[i].tag === "default" || layers[i].tag === tag) {
+					if (layers[i].tag === TAG.DEFAULT || layers[i].tag === tag) {
 						let layerPixels = layers[i].pixels;
 						let topMargin = maxHeight - layerPixels.length;
 						for (let y = 0; y < layerPixels.length; y++) {
@@ -488,8 +493,8 @@
 		 * @param {string} [tag]
 		 * @returns {string[][]}
 		 */
-		getPixels(tag = "default") {
-			return this.#pixelsByTag[tag] ?? this.#pixelsByTag["default"];
+		getPixels(tag = TAG.DEFAULT) {
+			return this.#pixelsByTag[tag] ?? this.#pixelsByTag[TAG.DEFAULT];
 		}
 
 		/**
diff --git a/src/animation/frame.js b/src/animation/frame.js
index d51515d..b623e41 100644
--- a/src/animation/frame.js
+++ b/src/animation/frame.js
@@ -1,6 +1,6 @@
 import { Directions } from '../shared.js';
 import { PALETTE, BirdType } from './sprites.js';
-import Layer from './layer.js';
+import Layer, { TAG } from './layer.js';
 
 class Frame {
 
@@ -16,10 +16,10 @@ class Frame {
 		for (let layer of layers) {
 			tags.add(layer.tag);
 		}
-		tags.add("default");
+		tags.add(TAG.DEFAULT);
 		for (let tag of tags) {
 			let maxHeight = layers.reduce((max, layer) => Math.max(max, layer.pixels.length), 0);
-			if (layers[0].tag !== "default") {
+			if (layers[0].tag !== TAG.DEFAULT) {
 				throw new Error("First layer must have the 'default' tag");
 			}
 			this.pixels = layers[0].pixels.map(row => row.slice());
@@ -29,7 +29,7 @@ class Frame {
 			}
 			// Combine layers
 			for (let i = 1; i < layers.length; i++) {
-				if (layers[i].tag === "default" || layers[i].tag === tag) {
+				if (layers[i].tag === TAG.DEFAULT || layers[i].tag === tag) {
 					let layerPixels = layers[i].pixels;
 					let topMargin = maxHeight - layerPixels.length;
 					for (let y = 0; y < layerPixels.length; y++) {
@@ -47,8 +47,8 @@ class Frame {
 	 * @param {string} [tag]
 	 * @returns {string[][]}
 	 */
-	getPixels(tag = "default") {
-		return this.#pixelsByTag[tag] ?? this.#pixelsByTag["default"];
+	getPixels(tag = TAG.DEFAULT) {
+		return this.#pixelsByTag[tag] ?? this.#pixelsByTag[TAG.DEFAULT];
 	}
 
 	/**
diff --git a/src/animation/layer.js b/src/animation/layer.js
index cd33990..72e6c95 100644
--- a/src/animation/layer.js
+++ b/src/animation/layer.js
@@ -1,9 +1,14 @@
+export const TAG = {
+	DEFAULT: "default",
+	TUFT: "tuft",
+};
+
 class Layer {
 	/**
 	 * @param {string[][]} pixels
 	 * @param {string} [tag]
 	 */
-	constructor(pixels, tag = "default") {
+	constructor(pixels, tag = TAG.DEFAULT) {
 		this.pixels = pixels;
 		this.tag = tag;
 	}
diff --git a/src/animation/sprites.js b/src/animation/sprites.js
index 9ff5e80..3aca274 100644
--- a/src/animation/sprites.js
+++ b/src/animation/sprites.js
@@ -1,3 +1,5 @@
+import { TAG } from "./layer.js";
+
 /**
  * Palette color names
  * @type {Record<string, string>}
@@ -105,7 +107,7 @@ export const SPECIES = {
 		[PALETTE.UNDERBELLY]: "#d7cfcb",
 		[PALETTE.WING]: "#b1b5c5",
 		[PALETTE.WING_EDGE]: "#9d9fa9",
-	}, ["tuft"]),
+	}, [TAG.TUFT]),
 	europeanRobin: new BirdType("European Robin",
 		"Native to western Europe, this is the quintessential robin. Quite friendly, you'll often find them searching for worms.", {
 		[PALETTE.FOOT]: "#af8e75",
@@ -127,7 +129,7 @@ export const SPECIES = {
 		[PALETTE.UNDERBELLY]: "#dc3719",
 		[PALETTE.WING]: "#d23215",
 		[PALETTE.WING_EDGE]: "#b1321c",
-	}, ["tuft"]),
+	}, [TAG.TUFT]),
 	americanGoldfinch: new BirdType("American Goldfinch",
 		"Coloured a brilliant yellow, this bird feeds almost entirely on the seeds of plants such as thistle, sunflowers, and coneflowers.", {
 		[PALETTE.BEAK]: "#ffaf34",