diff --git a/Gruntfile.js b/Gruntfile.js
index c6b34bb..05b2e5c 100644
--- a/Gruntfile.js
+++ b/Gruntfile.js
@@ -32,7 +32,8 @@ module.exports = function(grunt) {
           'js_src/utils.js',
           'js_src/sidebar.js',
           'js_src/Message.js',
-          'js_src/main.js'
+          'js_src/main.js',
+          'js_src/sketches.js'
         ],
         dest: 'www/js/<%= pkg.name %>.js'
       }
diff --git a/js_src/buttonbehaviors.js b/js_src/buttonbehaviors.js
index 590b273..9cd016a 100644
--- a/js_src/buttonbehaviors.js
+++ b/js_src/buttonbehaviors.js
@@ -45,6 +45,10 @@ function initButtonBehavior() {
 	btnNew.on('touchstart mousedown', clearDoodle);
 	btnPrint.on('touchstart mousedown', print);
 
+  getSavedSketchStatus();
+  setSketchModified(false);
+  //updatePrevNextButtonStateOnClear();
+
 //  btnClear.click(function(e) {
 //    e.preventDefault();
 //    //      console.log("clear");
@@ -205,13 +209,13 @@ function stopPrint() {
 }
 
 
-function prevDoodle(e) {
-  console.log("f:prevDoodle()");
-  console.log("f:prevDoodle()");
-}
-function nextDoodle(e) {
-  console.log("f:nextDoodle()");
-}
+// function prevDoodle(e) {
+//   console.log("f:prevDoodle()");
+//   console.log("f:prevDoodle()");
+// }
+// function nextDoodle(e) {
+//   console.log("f:nextDoodle()");
+// }
 
 function print(e) {
 	console.log("f:print() >> sendPrintCommands = " + sendPrintCommands);
@@ -302,6 +306,8 @@ function previewUp(redrawLess) {
   if (numLayers < maxNumLayers) {
     numLayers++;
   }
+  setSketchModified(true);
+
 //  redrawPreview(redrawLess);
   redrawRenderedPreview(redrawLess);
 }
@@ -310,6 +316,7 @@ function previewDown(redrawLess) {
   if (numLayers > minNumLayers) {
     numLayers--;
   }
+  setSketchModified(true);
 //  redrawPreview(redrawLess);
   redrawRenderedPreview(redrawLess);
 }
@@ -319,12 +326,14 @@ function previewTwistLeft(redrawLess) {
   if (rStep > -previewRotationLimit) rStep -= twistIncrement;
   //  redrawPreview(redrawLess);
   redrawRenderedPreview(redrawLess);
+  setSketchModified(true);
 }
 function previewTwistRight(redrawLess) {
   //    console.log("f:previewTwistRight()");
   if (rStep < previewRotationLimit) rStep += twistIncrement;
   //  redrawPreview(redrawLess);
   redrawRenderedPreview(redrawLess);
+  setSketchModified(true);
 }
 
 
@@ -407,20 +416,14 @@ function setState(newState,newHasControl) {
 	
 	/* save, next and prev buttons */
 	switch(newState) {
-		/*case Printer.WIFIBOX_DISCONNECTED_STATE:
+		case Printer.WIFIBOX_DISCONNECTED_STATE:
 			disableButton(btnPrevious);
 			disableButton(btnNext);
 			disableButton(btnSave);
 			break;
 		default:
-			enableButton(btnPrevious, null);
-			enableButton(btnNext, null);
-			enableButton(btnSave, null);
-			break;*/
-		default:
-			disableButton(btnPrevious);
-			disableButton(btnNext);
-			disableButton(btnSave);
+			updatePrevNextButtonState();
+			if (isModified) enableButton(btnSave, saveSketch);
 			break;
 	}
 
diff --git a/js_src/canvasDrawing.js b/js_src/canvasDrawing.js
index 593542c..c67a79d 100644
--- a/js_src/canvasDrawing.js
+++ b/js_src/canvasDrawing.js
@@ -29,6 +29,8 @@ var movementCounter = 0;
 var drawVariableLineWeight = false; // set to true to have the momentum of the mouse/touch movement result in larger/smaller strokes
 var lineweight = 2;
 
+var isModified = false;
+
 /* * * * * * * * * *
  *
  *  INIT
@@ -146,6 +148,8 @@ function draw(_x, _y, _width) {
 function clearDoodle() {
   console.log("f:clearDoodle");
 
+  updatePrevNextButtonStateOnClear();
+
   _points = [];
 
   prevX = 0;
@@ -162,6 +166,8 @@ function clearDoodle() {
   clearMainView();
   resetPreview();
   resetVerticalShapes();
+
+  setSketchModified(false);
 }
 
 function redrawDoodle(recalcBoundsAndTransforms) {
@@ -258,6 +264,8 @@ function adjustPreviewTransformation() {
  *
  * * * * * * * * * */
 function onCanvasMouseDown(e) {
+    setSketchModified(true);
+
 //  console.log("f:onCanvasMouseDown()");
   //  console.log("onCanvasMouseDown >> e.offsetX,e.offsetY = " + e.offsetX+","+e.offsetY);
   //  console.log("onCanvasMouseDown >> e.layerX,e.layerY= " + e.layerX+","+e.layerY);
@@ -285,8 +293,12 @@ function onCanvasMouseDown(e) {
 
 var prevPoint = {x:-1, y:-1};
 function onCanvasMouseMove(e) {
+
 //  console.log("f:onCanvasMouseMove()");
   if (!dragging) return;
+
+  setSketchModified(true);
+
   //    console.log("onmousemove");
 
   var x, y;
@@ -360,6 +372,8 @@ function onCanvasMouseUp(e) {
 }
 
 function onCanvasTouchDown(e) {
+  setSketchModified(true);
+
   e.preventDefault();
   console.log("f:onCanvasTouchDown >> e: " , e);
 //  var x = e.touches[0].pageX - e.touches[0].target.offsetLeft;
@@ -382,6 +396,8 @@ function onCanvasTouchDown(e) {
 }
 
 function onCanvasTouchMove(e) {
+  setSketchModified(true);
+
   e.preventDefault();
 //  var x = e.touches[0].pageX - e.touches[0].target.offsetLeft;
 //  var y = e.touches[0].pageY - e.touches[0].target.offsetTop;
@@ -458,4 +474,139 @@ function onCanvasTouchEnd(e) {
 
 function prevent(e) {
   e.preventDefault();
-}
\ No newline at end of file
+}
+
+
+//SVG validator: http://validator.w3.org/
+//SVG viewer: http://svg-edit.googlecode.com/svn/branches/2.6/editor/svg-editor.html
+function saveToSvg() {
+  var lastX = 0, lastY = 0, lastIsMove;
+  var svg = '';
+
+  var boundsWidth = doodleBounds[2] - doodleBounds[0];
+  var boundsHeight = doodleBounds[3] - doodleBounds[1];
+
+  svg += '<?xml version="1.0" standalone="no"?>\n';
+  svg += '<!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1//EN" "http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd">\n';
+  svg += '<svg width="' + boundsWidth + '" height="' + boundsHeight + '" version="1.1" xmlns="http://www.w3.org/2000/svg">\n';
+  svg += '\t<desc>Doodle 3D sketch</desc>\n';
+
+  var data = '';
+  for (var i = 0; i < _points.length; ++i) {
+    var x = _points[i][0], y = _points[i][1], isMove = _points[i][2];
+    var dx = x - lastX, dy = y - lastY;
+
+    if (i == 0)
+      data += 'M'; //emit absolute move on first pair of coordinates
+    else if (isMove != lastIsMove)
+      data += isMove ? 'm' : 'l';
+
+    data += dx + ',' + dy + ' ';
+
+    lastX = x;
+    lastY = y;
+    lastIsMove = isMove;
+  }
+
+  svg += '\t<path transform="translate(' + -doodleBounds[0] + ',' + -doodleBounds[1] + ')" d="' + data + '" fill="none" stroke="black" stroke-width="2" />\n';
+
+  var fields = JSON.stringify({'height': numLayers, 'outlineShape': VERTICALSHAPE, 'twist': rStep});
+  svg += '\t<!--<![CDATA[d3d-keys ' + fields + ']]>-->\n';
+
+  svg += '</svg>\n';
+
+  return svg;
+}
+
+
+//TODO: use local variables instead of _points,numLayers,VERTICALSHAPE and rStep so we can leave a current doodle in tact if an error occurs while parsing
+function loadFromSvg(svgData) {
+  var mode = '', x = 0, y = 0;
+
+  console.log("loading " + svgData.length + " bytes of data...");
+
+  clearDoodle();
+
+  var p = svgData.indexOf("<path");
+  if (p == -1) { console.log("loadFromSvg: could not find parsing start point"); return false; }
+  p = svgData.indexOf('d="', p);
+  if (p == -1) { console.log("loadFromSvg: could not find parsing start point"); return false; }
+  p += 3; //skip 'd="'
+
+  var skipSpace = function() { while (svgData.charAt(p) == ' ') p++; }
+  var parseCommand = function() {
+    while (true) {
+      skipSpace();
+      var c = svgData.charAt(p);
+      if (c == 'M' || c == 'm' || c == 'l') { //new command letter
+        mode = c;
+      } else if (c == '"') { //end of command chain
+        return true;
+      } else { //something else, must be a pair of coordinates...
+        var tx = 0, ty = 0, numberEnd = 0, len = 0;
+        numberEnd = svgData.indexOf(',', p);
+        if (numberEnd == -1) { console.log("could not find comma in coordinate pair"); return false; }
+        len = numberEnd - p;
+        tx = parseInt(svgData.substr(p, len));
+        p += len + 1;
+        skipSpace();
+        numberEnd = svgData.indexOf(' ', p);
+        if (numberEnd == -1) { console.log("could not find space after coordinate pair"); return false; }
+        len = numberEnd - p;
+        ty = parseInt(svgData.substr(p, len));
+        p += len;
+
+        if (mode == 'M' || mode == 'L') {
+          x = tx; y = ty;
+        } else if (mode == 'm' || mode == 'l') {
+          x += tx; y += ty;
+        } else {
+          console.log("loadFromSvg: found coordinate pair but mode was never set");
+          return false;
+        }
+
+        var isMove = mode == 'm' || mode == 'M';
+
+        //TODO: create script-wide function for adding points?
+        //console.log("inserting "+x+","+y+" ",isMove);
+        updatePrevX = x;
+        updatePrevY = y;
+        _points.push([x, y, isMove]);
+        adjustBounds(x, y);
+        adjustPreviewTransformation();
+
+        if (isMove) draw(x, y, .5);
+        else draw(x, y);
+      }
+      p++;
+    }
+
+    return true;
+  };
+
+  parseCommand(); //depends on value of p, so don't move this without taking that into consideration
+
+  const fieldDefMarker = "<!--<![CDATA[d3d-keys";
+  p = svgData.indexOf(fieldDefMarker);
+  if (p == -1) { console.log("loadFromSvg: could not find metadata marker"); return false; }
+  p += fieldDefMarker.length;
+  skipSpace();
+
+  var endP = svgData.indexOf("]]>-->", p);
+  if (endP == -1) { console.log("loadFromSvg: could not find metadata end-marker"); return false; }
+  var metaFields = JSON.parse(svgData.substr(p, endP - p));
+  //TODO: log error and return false if parsing failed
+  for (var k in metaFields) {
+    var v = metaFields[k];
+    switch (k) {
+      case "height": numLayers = v; break;
+      case "outlineShape": VERTICALSHAPE = v; break;
+      case "twist": rStep = v; break;
+    }
+  }
+
+  renderToImageDataPreview();
+
+  return true;
+}
+
diff --git a/js_src/sketches.js b/js_src/sketches.js
new file mode 100644
index 0000000..aecc9c5
--- /dev/null
+++ b/js_src/sketches.js
@@ -0,0 +1,156 @@
+var currentSketchId = 0;
+var numSavedSketches = 0;
+
+function getSavedSketchStatus() {
+	$.ajax({
+		url: wifiboxURL + "/sketch/status",
+		dataType: 'json',
+		type: 'GET',
+		//timeout: this.timeoutTime,
+		success: function(response) {
+			if (response.status == 'error' || response.status == 'fail') {
+				console.log("getSavedSketchStatus fail/error: " + response.msg + " -- ", response);
+			} else {
+				console.log("getSavedSketchStatus success: num. saved: " + response.data.number_of_sketches + ", space available: " + response.data.available);
+				numSavedSketches = response.data.number_of_sketches;
+				updatePrevNextButtonStateOnClear();
+			}
+		}
+	}).fail(function() {
+		console.log("getSavedSketchStatus failed: ", response);
+	});
+}
+
+function setSketchModified(_isModified, doNotClearCurrent) {
+	isModified = _isModified;
+
+	// alert("isModified: " + isModified);
+	//console.log("setModified: " + isModified + (typeof(doNotClearCurrent) !== 'undefined' ? " (doNotClearCurrent: "+doNotClearCurrent+")" : "")); //TEMP
+
+	if (isModified) enableButton(btnSave, saveSketch);
+	else disableButton(btnSave);
+
+	//if (typeof(doNotClearCurrent) !== 'undefined' && !doNotClearCurrent) setCurrentSketchId(-1);
+
+	
+	//sketchModified  = isModified; /// ERROR?
+}
+
+function setCurrentSketchId(sId) {
+	console.log("setCurrentSketchId: " + sId + " / " + numSavedSketches);
+	// var enablePrev = false;
+	// var enableNext = false;
+
+	currentSketchId = sId;
+
+	//clamp
+	if (currentSketchId > numSavedSketches) currentSketchId = numSavedSketches;
+	if (currentSketchId < 1) currentSketchId = 1;
+
+	//update textbox
+	//$("#txtSketch").val(currentSketchId);
+	
+	updatePrevNextButtonState();
+}
+
+function updatePrevNextButtonStateOnClear() {
+	enableButton(btnPrevious, prevDoodle);
+	disableButton(btnNext);
+	currentSketchId = numSavedSketches+1; //after the end of the list
+	disableButton(btnSave);
+}
+
+function updatePrevNextButtonState() {
+
+	//btnPrevious state
+	if (numSavedSketches==0 || currentSketchId < 2) {
+		disableButton(btnPrevious);
+	} else {
+		enableButton(btnPrevious, prevDoodle);
+	}
+
+	//btnNext state
+	if (numSavedSketches==0 || currentSketchId >= numSavedSketches) {
+		disableButton(btnNext);
+	} else {
+		enableButton(btnNext, nextDoodle);
+	}
+}
+
+function loadSketch(sketchId) {
+
+	$.ajax({
+		url: wifiboxURL + "/sketch/" + sketchId,
+		dataType: 'json',
+		type: 'GET',
+//			timeout: this.timeoutTime,
+		success: function(response) {
+			if (response.status == 'error' || response.status == 'fail') {
+				console.log("loadSketch fail/error: " + response.msg + " -- ", response);
+			} else {
+				console.log("loadSketch success: loaded id #" + response.data.id, response);
+				//console.log("sketch content:\n" + response.data.data);
+				if (loadFromSvg(response.data.data)) {
+					setSketchModified(false, true);
+					setCurrentSketchId(response.data.id);
+				}
+			}
+		}
+	}).fail(function() {
+		console.log("loadSketch failed: ", response);
+	});
+}
+
+//btnSave.mouseup(saveSketch);
+function saveSketch() {
+	svg = saveToSvg();
+	console.log("generated SVG [" + _points.length + " points, " + svg.length + " bytes]:\n" + svg);
+
+	$.ajax({
+		url: wifiboxURL + "/sketch",
+		dataType: 'json',
+		type: 'POST',
+		data: { data: svg },
+		//timeout: this.timeoutTime,
+		success: function(response) {
+			if (response.status == 'error' || response.status == 'fail') {
+				console.log("saveSketch fail/error: " + response.msg + " -- ", response);
+			} else {
+				console.log("saveSketch success: saved with id #" + response.data.id, response);
+				setSketchModified(false, true);
+				numSavedSketches = response.data.id;
+				setCurrentSketchId(response.data.id);
+			}
+		}
+	}).fail(function() {
+		console.log("saveSketch failed: ", response);
+	});
+}
+
+function prevDoodle(e) {
+  console.log("f:prevDoodle(): " + currentSketchId + " / " + numSavedSketches);
+  //alert('prev ' + numSavedSketches);
+  //return;
+
+  //TODO: if (enabled) {
+	  var sketchId = (currentSketchId > 0) ? currentSketchId : numSavedSketches;
+	  if (sketchId > 1) sketchId--;
+
+
+	  //alert(sketchId);
+
+	  loadSketch(sketchId);
+  //}
+}
+
+function nextDoodle(e) {
+  console.log("f:nextDoodle()");
+  //alert('next ' + numSavedSketches);
+  //return;
+
+  //TODO: if (enabled) {
+	  var sketchId = (currentSketchId > 0) ? currentSketchId : numSavedSketches;
+	  if (sketchId < numSavedSketches) sketchId++;
+	  loadSketch(sketchId);
+  //}
+}
diff --git a/www/index.html b/www/index.html
index 1c48353..9fda06e 100644
--- a/www/index.html
+++ b/www/index.html
@@ -32,9 +32,10 @@
   <div class="leftpanel shadowright">
     <div class='sidebutton shadowright'></div>
     <img class="btnNew btn" src="img/buttons/btnNew.png" /><br/>
-    <div class="btnsPrevNext">
+    <div class="btnsPrevNext" style="text-align:center">
       <img class="btnPrevious btn" src="img/buttons/btnLeft.png">
       <img class="btnNext btn" src="img/buttons/btnRight.png">
+      <!-- <div id="txtSketch"></div> -->
     </div>
     <img class="btnSave btn" src="img/buttons/btnSave.png" /><br/>
     <img class="btnOops btn" src="img/buttons/btnOops.png" /><br/>