diff --git a/src/mesh/api.js b/src/mesh/api.js
index 0117e6fe..50b4c21a 100644
--- a/src/mesh/api.js
+++ b/src/mesh/api.js
@@ -443,11 +443,12 @@ let sketch = {
     },
 
     extrude(opt = {}) {
-        if (!selection.sketch()) {
+        let sketch = selection.sketch();
+        if (!sketch) {
             return log('select a sketch to extrude');
         }
         api.modal.dialog({
-            title: "gear generator",
+            title: "extrude",
             body: [ h.div({ class: "addgear" }, [
                 h.label('height'),
                 h.input({ value: opt.height || 10, size: 5, id: "_height" }),
@@ -460,7 +461,8 @@ let sketch = {
                 h.input({ value: opt.chamfer_bottom || 0, size: 5, id: "_chambot" }),
                 h.button({ _: "create", onclick() {
                     const { _height, _chamtop, _chambot } = api.modal.bound;
-                    selection.sketch()?.extrude({
+                    sketch.extrude({
+                        selection: sketch.selection.count() > 0,
                         ...opt,
                         height: parseFloat(_height.value),
                         chamfer_top: parseFloat(_chamtop.value),
@@ -473,6 +475,27 @@ let sketch = {
         api.modal.bound._height.focus();
     },
 
+    arrange: {
+        group() {
+            let one = sketch.selection.one;
+            let items = one?.items.filter(i => i.selected);
+            if (items.length > 1) {
+                let group = Date.now().toString(36);
+                items.forEach(i => i.group = group);
+                log('grouped', items.length, 'sketch items');
+            }
+        },
+
+        ungroup() {
+            let one = sketch.selection.one;
+            let items = one?.items.filter(i => i.selected)
+            if (items.length > 1) {
+                items.forEach(i => delete i.group);
+                log('ungrouped', items.length, 'sketch items');
+            }
+        }
+    },
+
     selection: {
         get one() {
             return selection.sketch();
@@ -502,6 +525,10 @@ let sketch = {
             sketch.selection.one?.boolean.flatten();
         },
 
+        evenodd() {
+            sketch.selection.one?.boolean.evenodd();
+        },
+
         union() {
             sketch.selection.one?.boolean.union();
         },
diff --git a/src/mesh/build.js b/src/mesh/build.js
index b68a4876..1f13eae8 100644
--- a/src/mesh/build.js
+++ b/src/mesh/build.js
@@ -425,6 +425,14 @@ function ui_build() {
                 h.button({ _: 'difference', onclick: tool.difference }),
             ])
         ]),
+        h.div({ class: "sketch-on" }, [
+            h.div({ _: "arrange", class: "head" }),
+            h.div({ class: "back"}),
+            h.div({ class: "pop"}, [
+                h.button({ _: 'group', onclick: sketch.arrange.group }),
+                h.button({ _: 'ungroup', onclick: sketch.arrange.ungroup }),
+            ])
+        ]),
         h.div({ class: "sketch-on" }, [
             h.div({ _: "boolean", class: "head" }),
             h.div({ class: "back"}),
@@ -433,6 +441,7 @@ function ui_build() {
                 h.button({ _: 'intersect', onclick: sketch.boolean.intersect }),
                 h.button({ _: 'difference', onclick: sketch.boolean.difference }),
                 h.hr(),
+                h.button({ _: 'even/odd', onclick: sketch.boolean.evenodd }),
                 h.button({ _: 'nest', onclick: sketch.boolean.nest }),
                 h.button({ _: 'flatten', onclick: sketch.boolean.flatten }),
             ])
diff --git a/src/mesh/sketch.js b/src/mesh/sketch.js
index 01fb654b..7c9684eb 100644
--- a/src/mesh/sketch.js
+++ b/src/mesh/sketch.js
@@ -141,6 +141,14 @@ mesh.sketch = class MeshSketch extends mesh.object {
                 return sketch.group.children.filter(c => c.sketch_item && c.sketch_item.selected);
             },
 
+            items() {
+                return sketch.selection.mesh_items().map(i => c.sketch_item.item);
+            },
+
+            count() {
+                return sketch.selection.mesh_items().length;
+            },
+
             all() {
                 sketch.items.forEach(i => i.selected = true);
                 sketch.render();
@@ -229,6 +237,18 @@ mesh.sketch = class MeshSketch extends mesh.object {
                 }
             },
 
+            evenodd() {
+                let items = sketch.selection.mesh_items();
+                // if (items.length < 2) return log('operation requires at least 2 items');
+                let polys = items.map(i => i.sketch_item.poly);
+                let even = POLYS.nest(POLYS.flatten(polys.clone(true), [], true));
+                let odd = POLYS.nest(POLYS.flatten(even.clone(true), [], true).filter(p => p.depth > 0));
+                sketch.selection.delete();
+                for (let poly of [...even, ...odd]) {
+                    sketch.add_polygon({ poly });
+                }
+            },
+
             flatten() {
                 let items = sketch.selection.mesh_items();
                 let polys = items.map(i => i.sketch_item.poly).clone(true);
@@ -346,6 +366,7 @@ mesh.sketch = class MeshSketch extends mesh.object {
         log(this.file || this.id, '| add circle');
         this.items.push({
             type: "circle",
+            selected: true,
             ...Object.assign({}, { center: {x:0, y:0, z:0}, radius:5 }, opt)
         });
         this.render();
@@ -355,6 +376,7 @@ mesh.sketch = class MeshSketch extends mesh.object {
         log(this.file || this.id, '| add rectangle');
         this.items.push({
             type: "rectangle",
+            selected: true,
             ...Object.assign({}, { center: {x:0, y:0, z:0}, width:15, height:10 }, opt)
         });
         this.render();
@@ -366,6 +388,7 @@ mesh.sketch = class MeshSketch extends mesh.object {
         delete opt.poly;
         this.items.push({
             type: "polygon",
+            selected: true,
             ...Object.assign({}, { center: {x:0, y:0, z:0} }, opt),
             ...poly.toObject()
         });
@@ -386,6 +409,7 @@ mesh.sketch = class MeshSketch extends mesh.object {
     }
 
     extrude(opt = {}) {
+        console.log('extrude',opt);
         let { selection, height, chamfer, chamfer_top, chamfer_bottom } = opt;
         let models = [];
         let items = this.group.children
@@ -427,9 +451,15 @@ class SketchItem {
     }
 
     toggle() {
-        this.item.selected = !this.item.selected;
+        let { sketch, item } = this;
+        item.selected = !item.selected;
+        if (item.group) {
+            sketch.items
+                .filter(i => i.group === item.group)
+                .forEach(i => i.selected = item.selected);
+        }
         this.update();
-        this.sketch.render();
+        sketch.render();
         broker.publish('sketch_selections');
     }