diff --git a/gui.js b/gui.js
index 0b39e49..d3a045d 100644
--- a/gui.js
+++ b/gui.js
@@ -6,7 +6,8 @@ const DEFAULTS = {
 	nodesize: 1.25,
 	linkopacity: 0.5,
 	link2opacity: 0.5,
-	shape: '120-cell inscribed',
+	shape: '',
+	option: '',
 	visibility: 5,
 	inscribed: false,
 	inscribe_all: false,
@@ -24,10 +25,16 @@ class FourDGUI {
 
 	constructor(shapes, changeShape, setColor, setBackground, setLinkOpacity, setVisibility) {
 		this.gui = new GUI();
+		const SHAPE_NAMES = shapes.map((s) => s.name);
+		// set default shape + option from the first shape
+		DEFAULTS.shape = shapes[0].name;
+		DEFAULTS.option = shapes[0].options[0].name;
+
 		this.parseLinkParams();
 		const guiObj = this;
 		this.params = {
 			shape: this.link['shape'],
+			option: this.link['option'],
 			inscribed: this.link['inscribed'],
 			inscribe_all: this.link['inscribe_all'],
 			thickness: this.link['thickness'],
@@ -44,7 +51,6 @@ class FourDGUI {
 			dpsi: this.link['dpsi'],
 			"copy link": function () { guiObj.copyUrl() }
 		};
-		const SHAPE_NAMES = shapes.map((s) => s.name);
 		let options_ctrl;
 		this.gui.add(this.params, 'shape', SHAPE_NAMES).onChange((shape) => {
 			const options = this.getShapeOptions(shapes, shape);
@@ -54,7 +60,7 @@ class FourDGUI {
 			changeShape(shape)
 		});
 		const options = this.getShapeOptions(shapes, this.params['shape']);
-		options_ctrl = this.gui.add(this.params, 'options', options).onChange((option) => {
+		options_ctrl = this.gui.add(this.params, 'option', options).onChange((option) => {
 			setVisibility(option)
 		});
 		this.gui.add(this.params, 'hyperplane', 1.5, 2.25);
@@ -111,7 +117,7 @@ class FourDGUI {
 		const guiObj = this;
 
 		this.urlParams = this.linkUrl.searchParams;
-		for( const param of [ "shape", "rotation", "visiblity" ]) {
+		for( const param of [ "shape", "rotation", "option" ]) {
 			const value = this.urlParams.get(param);
 			if( value ) {
 				this.link[param] = value;
@@ -137,6 +143,7 @@ class FourDGUI {
 	copyUrl() {
 		const url = new URL(this.linkUrl.origin + this.linkUrl.pathname);
 		url.searchParams.append("shape", this.params.shape);
+		url.searchParams.append("option", this.params.option);
 		url.searchParams.append("inscribed", this.params.inscribed ? 'y': 'n');
 		url.searchParams.append("inscribe_all", this.params.inscribe_all ? 'y': 'n');
 		url.searchParams.append("thickness", this.params.thickness.toString());
diff --git a/main.js b/main.js
index e23521e..b9dc28e 100644
--- a/main.js
+++ b/main.js
@@ -74,14 +74,14 @@ let node_show = [];
 let link_show = []; 
 
 
-function createShape(name) {
+function createShape(name, option) {
 	if( shape ) {
 		scene.remove(shape);
 	}
 	structure = STRUCTURES_BY_NAME[name];
 	shape = new FourDShape(node_ms, link_ms, face_ms, structure);
 	scene.add(shape);
-	setVisibility(structure.options[0].name);
+	setVisibility(option ? option : structure.options[0].name);
 }
 
 // initialise gui and read params from URL
@@ -177,7 +177,7 @@ renderer.domElement.addEventListener("pointerup", (event) => {
 	dragging = false;
 })
 
-createShape(gui.params.shape);
+createShape(gui.params.shape, gui.params.option);
 
 function animate() {
 	requestAnimationFrame( animate );