diff --git a/src/kiri/conf.js b/src/kiri/conf.js
index d937d885..ef4f52f5 100644
--- a/src/kiri/conf.js
+++ b/src/kiri/conf.js
@@ -577,6 +577,7 @@
                     outputLaserGroup: true,
                     outputLaserZColor: false,
                     outputLaserLayer: false,
+                    outputLaserStack: false,
                     outputLaserMerged: false,
                     outputOriginCenter: true,
                     outputInvertX: false,
diff --git a/src/kiri/init.js b/src/kiri/init.js
index 73a15bf8..68e88bd1 100644
--- a/src/kiri/init.js
+++ b/src/kiri/init.js
@@ -1729,6 +1729,7 @@
             laserOffset:         UC.newInput(LANG.ls_offs_s, {title:LANG.ls_offs_l, convert:UC.toFloat, modes:LASER}),
             laserSliceHeight:    UC.newInput(LANG.ls_lahi_s, {title:LANG.ls_lahi_l, convert:UC.toFloat, modes:LASER, trigger: true}),
             laserSliceHeightMin: UC.newInput(LANG.ls_lahm_s, {title:LANG.ls_lahm_l, convert:UC.toFloat, modes:LASER, show:() => { return UI.laserSliceHeight.value == 0 }}),
+            laserSep:            UC.newBlank({class:"pop-sep", modes:LASER}),
             laserSliceSingle:    UC.newBoolean(LANG.ls_sngl_s, onBooleanClick, {title:LANG.ls_sngl_l, modes:LASER}),
 
             firstLayer:          UC.newGroup(LANG.fl_menu, null, {modes:FDM}),
@@ -1845,8 +1846,11 @@
             output:              UC.newGroup(LANG.ou_menu, null, {modes:GCODE}),
             outputLaserPower:    UC.newInput(LANG.ou_powr_s, {title:LANG.ou_powr_l, convert:UC.toInt, bound:UC.bound(1,100), modes:LASER}),
             outputLaserSpeed:    UC.newInput(LANG.ou_sped_s, {title:LANG.ou_sped_l, convert:UC.toInt, modes:LASER}),
+            laserSep:            UC.newBlank({class:"pop-sep", modes:LASER}),
             outputLaserZColor:   UC.newBoolean(LANG.ou_layo_s, onBooleanClick, {title:LANG.ou_layo_l, modes:LASER, show:() => { return UI.outputLaserMerged.checked === false }}),
             outputLaserLayer:    UC.newBoolean(LANG.ou_layr_s, onBooleanClick, {title:LANG.ou_layr_l, modes:LASER}),
+            outputLaserStack:    UC.newBoolean(LANG.ou_lays_s, onBooleanClick, {title:LANG.ou_lays_l, modes:LASER}),
+            laserSep:            UC.newBlank({class:"pop-sep", modes:LASER}),
 
             outputTemp:          UC.newInput(LANG.ou_nozl_s, {title:LANG.ou_nozl_l, convert:UC.toInt, modes:FDM}),
             outputBedTemp:       UC.newInput(LANG.ou_bedd_s, {title:LANG.ou_bedd_l, convert:UC.toInt, modes:FDM}),
diff --git a/src/mode/laser/driver.js b/src/mode/laser/driver.js
index 76ced0d9..4dc8c9a2 100644
--- a/src/mode/laser/driver.js
+++ b/src/mode/laser/driver.js
@@ -68,28 +68,43 @@
         });
     };
 
-    function sliceEmitObjects(print, slice, groups, simple) {
+    function sliceEmitObjects(print, slice, groups, opt = { }) {
         let start = newPoint(0,0,0);
         let process = print.settings.process;
         let grouped = process.outputLaserGroup;
+        let stacked = process.outputLaserStack;
+        let simple = opt.simple || false;
         let group = [];
+        let emit = { in: [], out: [], mark: [] };
+        let lastEmit = opt.lastEmit;
         let zcolor = print.settings.process.outputLaserZColor;
 
         group.thick = slice.thick;
 
-        function laserOut(poly, group) {
+        function laserOut(poly, group, type) {
             if (!poly) {
                 return;
             }
             if (Array.isArray(poly)) {
                 poly.forEach(function(pi) {
-                    laserOut(pi, group);
+                    laserOut(pi, group, type);
                 });
             } else {
-                let pathOpt = zcolor ? {extrude: slice.z, rate: slice.z} : {extrude: 1};
+                let pathOpt = zcolor ? {extrude: slice.z, rate: slice.z} : {extrude: 1, rate: 1};
+                if (type === "mark") {
+                    pathOpt.rate = 0.001;
+                }
                 if (simple) pathOpt.simple = true;
                 if (poly.open) pathOpt.open = true;
+                emit[type].push(poly);
                 print.polyPrintPath(poly, start, group, pathOpt);
+                if (stacked && type === "out" && lastEmit) {
+                    for (let out of lastEmit.out) {
+                        if (out.isInside(poly)) {
+                            laserOut(out, group, "mark");
+                        }
+                    }
+                }
             }
         }
 
@@ -97,8 +112,8 @@
         let inner = offset.map(poly => poly.inner || []).flat();
 
         // cut inside before outside
-        laserOut(inner, group);
-        laserOut(offset, group);
+        laserOut(inner, group, "in");
+        laserOut(offset, group, "out");
 
         if (!grouped) {
             groups.push(group);
@@ -109,6 +124,8 @@
         if (grouped) {
             groups.push(group);
         }
+
+        return emit;
     };
 
     /**
@@ -246,10 +263,11 @@
                         });
                     });
                 }
-                widget.slices.forEach(function(slice) {
-                    sliceEmitObjects(print, slice, output, knifeOn);
+                let lastEmit;
+                for (let slice of widget.slices.reverse()) {
+                    lastEmit = sliceEmitObjects(print, slice, output, {simple: knifeOn, lastEmit});
                     update((slices++ / totalSlices) * 0.5, "prepare");
-                });
+                }
             }
         });
 
diff --git a/web/kiri/lang/en.js b/web/kiri/lang/en.js
index ad0ccfc1..6097b76f 100644
--- a/web/kiri/lang/en.js
+++ b/web/kiri/lang/en.js
@@ -546,6 +546,8 @@ kiri.lang['en-us'] = {
     ou_layr_l:      ["output layer order","from top right to","bottom left"],
     ou_layo_s:      "layer color",
     ou_layo_l:      ["output layer colors","for each z index","overridden by merged"],
+    ou_lays_s:      "layer stacking",
+    ou_lays_l:      ["mark layers for stacking","with a unique color"],
     ou_drkn_s:      "drag knife",
     ou_drkn_l:      ["enable drag knife","output in gcode","cut radii are added","to corners with","cut down passes"],