diff --git a/js/geo-polygon.js b/js/geo-polygon.js
index f65d746a..f23233fc 100644
--- a/js/geo-polygon.js
+++ b/js/geo-polygon.js
@@ -112,14 +112,18 @@ var gs_base_polygon = exports;
      * Polygon Prototype Functions
      ******************************************************************* */
 
-    PRO.toString = function() {
+    PRO.toString = function(verbose) {
         let l;
         if (this.inner && this.inner.length) {
-            l = '/' + this.inner.map(i => i.toString()).join(',');
+            l = '/' + this.inner.map(i => i.toString(verbose)).join(',');
         } else {
             l = '';
         }
-        return `P[${this.points.length,this.area().toFixed(2)}${l}]`;
+        if (verbose) {
+            return `P[{${this.area().toFixed(2)}}[${this.points.length}](${this.points.map(p=>`${p.x},${p.y}`).join('|')})${l}]`;
+        } else {
+            return `P[${this.points.length,this.area().toFixed(2)}${l}]`;
+        }
     };
 
     // return which plane (x,y,z) this polygon is coplanar with
@@ -1069,6 +1073,9 @@ var gs_base_polygon = exports;
      * @returns {?Polygon[]} returns output array provided as input or new array if not provided
      */
     PRO.offset = function(offset, output) {
+        // let offs = geo.poly.offset([this], -offset, this.getZ());
+        // if (output) output.appendAll(offs);
+        // return output || offs;
         return POLY().expand([this], -offset, this.getZ(), output);
     };
 
diff --git a/js/geo-wasm.js b/js/geo-wasm.js
index 4bcde68d..0f75c0df 100644
--- a/js/geo-wasm.js
+++ b/js/geo-wasm.js
@@ -68,7 +68,35 @@ if (!self.window)
             }
         }
         wasm.free(memat);
-        return out;
+        return polyNest(out);
+    }
+
+    // nest closed polygons without existing parent / child relationships
+    function polyNest(polys) {
+        polys.sort((a,b) => {
+            return b.bounds.minx - a.bounds.minx;
+        });
+        // from smallest to largest, check for enclosing bounds and nest
+        for (let i=0, il=polys.length; i<il; i++) {
+            let smaller = polys[i];
+            // prevent parent poly from being consumed
+            if (smaller.inner) continue;
+            for (let j=i+1; j<il; j++) {
+                let larger = polys[j];
+                if (larger.bounds.contains(smaller.bounds)) {
+                    larger.addInner(smaller);
+                    break;
+                }
+            }
+        }
+        let tops = [];
+        for (let i=0, il=polys.length; i<il; i++) {
+            let poly = polys[i];
+            if (!poly.parent) {
+                tops.push(poly);
+            }
+        }
+        return tops;
     }
 
     fetch('/wasm/kiri-geo.wasm')
@@ -101,29 +129,6 @@ if (!self.window)
             };
 
             wasm.start();
-
-            // console.log(polyOffset(
-            //     [ self.base.newPolygon().centerRectangle({x:6,y:6},10,10) ], 1
-            // ));
-
-            // let memat = wasm.malloc(4096);
-            // let writer = new DataWriter(heap, memat);
-            // let pcount = writePoly(writer, self.base.newPolygon().centerRectangle({x:6,y:6},10,10));
-            //
-            // log({instance, exports, heap, memat});
-            // log(wasm.heap.buffer.slice(memat, memat+100));
-            //
-            // let resat = wasm.offset(memat, pcount, 0.5 * factor);
-            //
-            // log('offset', resat);
-            //
-            // log(wasm.heap.buffer.slice(resat, resat+100));
-            //
-            // let reader = new DataReader(heap, resat);
-            // let poly = readPoly(reader);
-            // console.log({poly});
-            //
-            // wasm.free(memat);
         });
 
 })();
diff --git a/wasm/kiri-geo.cpp b/wasm/kiri-geo.cpp
index 1e993f98..bb19c418 100644
--- a/wasm/kiri-geo.cpp
+++ b/wasm/kiri-geo.cpp
@@ -58,6 +58,12 @@ Uint32 poly_offset(Uint32 memat, Uint32 polys, float offset) {
         poly++;
     }
 
+    // clean and simplify polygons
+    // Paths cleans, simples;
+    // CleanPolygons(ins, cleans, 250);
+    // SimplifyPolygons(cleans, simples, pftNonZero);
+    // ins = simples;
+
     ClipperOffset co;
     co.AddPaths(ins, jtMiter, etClosedPolygon);
     co.Execute(outs, offset);
@@ -65,19 +71,23 @@ Uint32 poly_offset(Uint32 memat, Uint32 polys, float offset) {
     Uint32 resat = pos;
 
     for (Path po : outs) {
-        // polygon(po.size(), 0);
+        // polygon(po.size(), 1);
         struct length16 *ls = (struct length16 *)(mem + pos);
         ls->length = po.size();
         pos += 2;
         for (IntPoint pt : po) {
             // point(pt.X, pt.Y);
             struct point32 *ip = (struct point32 *)(mem + pos);
-            ip->x = pt.X;
-            ip->y = pt.Y;
+            ip->x = (int)pt.X;
+            ip->y = (int)pt.Y;
             pos += 8;
         }
     }
 
+    // null terminate
+    struct length16 *ls = (struct length16 *)(mem + pos);
+    ls->length = 0;
+
     co.Clear();
 
     return resat;
diff --git a/wasm/kiri-geo.wasm b/wasm/kiri-geo.wasm
index cc9ea758..989dbfad 100644
Binary files a/wasm/kiri-geo.wasm and b/wasm/kiri-geo.wasm differ