diff --git a/contributors.md b/contributors.md
index 2822d2e6..6f41fbc2 100644
--- a/contributors.md
+++ b/contributors.md
@@ -8,6 +8,7 @@ The following people have contributed to the development of jsPsych by writing c
 * Gustavo Juantorena - https://github.com/GEJ1
 * Chris Jungerius - https://github.com/cjungerius
 * Jana Klaus - https://github.com/janakl4us
+* Peter Jes Kohler - https://github.com/pjkohler 
 * Jonas Lambers
 * Shane Martin - https://github.com/shamrt
 * Adrian Oesch - https://github.com/adrianoesch
diff --git a/docs/plugins/jspsych-free-sort.md b/docs/plugins/jspsych-free-sort.md
index 3c6e119c..1d9ba5bb 100644
--- a/docs/plugins/jspsych-free-sort.md
+++ b/docs/plugins/jspsych-free-sort.md
@@ -15,13 +15,14 @@ Parameter | Type | Default Value | Description
 stimuli | array | *undefined* | Each element of this array is an image path.
 stim_height | numeric | 100 | The height of the images in pixels.
 stim_width | numeric | 100 | The width of the images in pixels.
+scale_factor | numeric | 1.5 | How much larger to make the stimulus while moving (1 = no scaling).
 sort_area_height | numeric | 800 | The height of the container that subjects can move the stimuli in. Stimuli will be constrained to this area.
 sort_area_width | numeric | 800 | The width of the container that subjects can move the stimuli in. Stimuli will be constrained to this area.
+sort_area_shape | string | "ellipse" | The shape of the sorting area, can be "ellipse" or "square".
 prompt | string | null | This string can contain HTML markup. The intention is that it can be used to provide a reminder about the action the subject is supposed to take (e.g., which key to press).
 prompt_location | string | "above" | Indicates whether to show the prompt `"above"` or `"below"` the sorting area.
 button_label | string |  'Continue' | The text that appears on the button to continue to the next trial.
 
-
 ## Data Generated
 
 In addition to the [default data collected by all plugins](overview#data-collected-by-plugins), this plugin collects the following data for each trial.
diff --git a/examples/jspsych-free-sort.html b/examples/jspsych-free-sort.html
index 79dd0448..387c0992 100644
--- a/examples/jspsych-free-sort.html
+++ b/examples/jspsych-free-sort.html
@@ -10,7 +10,12 @@
 
   var trials = {
     type: 'free-sort',
-    stimuli: ['img/happy_face_1.jpg','img/happy_face_2.jpg','img/happy_face_3.jpg','img/happy_face_4.jpg']
+    stimuli: ['img/happy_face_1.jpg','img/happy_face_2.jpg','img/happy_face_3.jpg','img/happy_face_4.jpg'],
+    stim_height: 150,
+    stim_width: 200,
+    scale_factor: 1.3,
+    sort_area_shape: "ellipse",
+    prompt_location: "below"
   };
 
 
diff --git a/plugins/jspsych-free-sort.js b/plugins/jspsych-free-sort.js
index e498d7e3..80ff49d8 100644
--- a/plugins/jspsych-free-sort.js
+++ b/plugins/jspsych-free-sort.js
@@ -22,19 +22,25 @@ jsPsych.plugins['free-sort'] = (function() {
         pretty_name: 'Stimuli',
         default: undefined,
         array: true,
-        description: 'Images to be displayed.'
+        description: 'items to be displayed.'
       },
       stim_height: {
         type: jsPsych.plugins.parameterType.INT,
         pretty_name: 'Stimulus height',
         default: 100,
-        description: 'Height of images in pixels.'
+        description: 'Height of items in pixels.'
       },
       stim_width: {
         type: jsPsych.plugins.parameterType.INT,
         pretty_name: 'Stimulus width',
         default: 100,
-        description: 'Width of images in pixels'
+        description: 'Width of items in pixels'
+      },
+      scale_factor: {
+        type: jsPsych.plugins.parameterType.FLOAT,
+        pretty_name: 'Stimulus scaling factor',
+        default: 1.5,
+        description: 'How much larger to make the stimulus while moving (1 = no scaling)'
       },
       sort_area_height: {
         type: jsPsych.plugins.parameterType.INT,
@@ -48,10 +54,17 @@ jsPsych.plugins['free-sort'] = (function() {
         default: 800,
         description: 'The width of the container that subjects can move the stimuli in.'
       },
+      sort_area_shape: {
+        type: jsPsych.plugins.parameterType.STRING,
+        pretty_name: 'Sort area shape',
+        options: ['square','ellipse'],
+        default: 'ellipse',
+        description: 'The shape of the sorting area'
+      },
       prompt: {
         type: jsPsych.plugins.parameterType.STRING,
         pretty_name: 'Prompt',
-        default: null,
+        default: '',
         description: 'It can be used to provide a reminder about the action the subject is supposed to take.'
       },
       prompt_location: {
@@ -64,7 +77,7 @@ jsPsych.plugins['free-sort'] = (function() {
       button_label: {
         type: jsPsych.plugins.parameterType.STRING,
         pretty_name: 'Button label',
-        default:  'Continue',
+        default:  'continue',
         description: 'The text that appears on the button to continue to the next trial.'
       }
     }
@@ -74,36 +87,96 @@ jsPsych.plugins['free-sort'] = (function() {
 
     var start_time = performance.now();
 
-    var html = "";
-    // check if there is a prompt and if it is shown above
-    if (trial.prompt !== null && trial.prompt_location == "above") {
-      html += trial.prompt;
-    }
-
-    html += '<div '+
+    let html = 
+      '<div '+
       'id="jspsych-free-sort-arena" '+
       'class="jspsych-free-sort-arena" '+
-      'style="position: relative; width:'+trial.sort_area_width+'px; height:'+trial.sort_area_height+'px; border:2px solid #444;"'+
-      '></div>';
+      'style="position: relative; width:'+trial.sort_area_width+'px; height:'+trial.sort_area_height+'px; margin: auto; line-height: 0em"</div>';
 
-    // check if prompt exists and if it is shown below
-    if (trial.prompt !== null && trial.prompt_location == "below") {
-      html += trial.prompt;
+    // another div for border
+    html += '<div '+
+      'id="jspsych-free-sort-border" '+
+      'class="jspsych-free-sort-border" '+
+      'style="position: relative; width:'+trial.sort_area_width*.94+'px; height:'+trial.sort_area_height*.94+'px; border:'+trial.sort_area_height*.03+'px solid #fc9272; margin: auto; line-height: 0em; ';
+    
+    if ( trial.sort_area_shape == "ellipse") {
+      html += 'webkit-border-radius: 50%; moz-border-radius: 50%; border-radius: 50%"></div>'
+    } else {
+      html += 'webkit-border-radius: 0%; moz-border-radius: 0%; border-radius: 0%"></div>'
     }
 
+    if ( trial.prompt ) {
+      trial.prompt = '<br>'
+    }
+    else {
+      trial.prompt = ''
+    }
+
+    // variable that has the prompt text, counter and button
+    const html_text = '<div style="line-height: 0em">' + trial.prompt + 
+      '<p id="jspsych-free-sort-counter" style="display: inline-block; line-height: 1em">You still need to place ' + trial.stimuli.length + ' items inside the arena.</p>'+
+      '<button id="jspsych-free-sort-done-btn" class="jspsych-btn" '+ 
+      'style="display: none; margin: 5px; padding: 5px; text-align: center; font-weight: bold; font-size: 18px; vertical-align:baseline; line-height: 1em">' + trial.button_label+'</button></div>'
+    
+    // position prompt above or below
+    if (trial.prompt_location == "below") {
+        html += html_text
+    } else {
+        html = html_text + html
+    }
+
+    console.log(html)
     display_element.innerHTML = html;
 
     // store initial location data
-    var init_locations = [];
+    let init_locations = [];
 
-    for (var i = 0; i < trial.stimuli.length; i++) {
-      var coords = random_coordinate(trial.sort_area_width - trial.stim_width, trial.sort_area_height - trial.stim_height);
+    // determine number of rows and colums, must be a even number
+    let num_rows = Math.ceil(Math.sqrt(trial.stimuli.length))
+    if ( num_rows % 2 != 0) {
+      num_rows = num_rows + 1
+    }
 
+    // compute coords for left and right side of arena
+    let r_coords = [];
+    let l_coords = [];
+    for (const x of make_arr(0, trial.sort_area_width - trial.stim_width, num_rows) ) {
+      for (const y of make_arr(0, trial.sort_area_height - trial.stim_height, num_rows) ) {
+        if ( x > ( (trial.sort_area_width - trial.stim_width)  * .5 ) ) {
+          //r_coords.push({ x:x, y:y } )
+          r_coords.push({ x:x + (trial.sort_area_width)  * .5 , y:y });
+        } else {
+          l_coords.push({ x:x - (trial.sort_area_width)  * .5 , y:y });
+          //l_coords.push({ x:x, y:y } )
+        }
+      }
+    }
+
+    // repeat coordinates until you have enough coords (may be obsolete)
+    while ( ( r_coords.length + l_coords.length ) < trial.stimuli.length ) {
+      r_coords = r_coords.concat(r_coords)
+      l_coords = l_coords.concat(l_coords)
+    }
+    // reverse left coords, so that coords closest to arena is used first
+    l_coords = l_coords.reverse()
+
+    // shuffle stimuli, so that starting positions are random
+    trial.stimuli = shuffle(trial.stimuli);
+
+    let inside = []
+    for (let i = 0; i < trial.stimuli.length; i++) {
+      let coords = []
+      if ( (i % 2) == 0 ) {
+        coords = r_coords[Math.floor(i * .5)];
+      } else {
+        coords = l_coords[Math.floor(i * .5)];
+      }
       display_element.querySelector("#jspsych-free-sort-arena").innerHTML += '<img '+
         'src="'+trial.stimuli[i]+'" '+
         'data-src="'+trial.stimuli[i]+'" '+
         'class="jspsych-free-sort-draggable" '+
         'draggable="false" '+
+        'id="'+i+'" '+
         'style="position: absolute; cursor: move; width:'+trial.stim_width+'px; height:'+trial.stim_height+'px; top:'+coords.y+'px; left:'+coords.x+'px;">'+
         '</img>';
 
@@ -112,31 +185,74 @@ jsPsych.plugins['free-sort'] = (function() {
         "x": coords.x,
         "y": coords.y
       });
+      inside.push(false);
     }
+    // moves within a trial
+    let moves = [];
 
-    display_element.innerHTML += '<button id="jspsych-free-sort-done-btn" class="jspsych-btn">'+trial.button_label+'</button>';
+    // are objects currently inside
+    let cur_in = false
 
-    var maxz = 1;
+    // draggable items 
+    const draggables = display_element.querySelectorAll('.jspsych-free-sort-draggable');
 
-    var moves = [];
+    // button (will show when all items are inside) and border (will change color)
+    const border = display_element.querySelector("#jspsych-free-sort-border")
+    const button = display_element.querySelector('#jspsych-free-sort-done-btn')
 
-    var draggables = display_element.querySelectorAll('.jspsych-free-sort-draggable');
-
-    for(var i=0;i<draggables.length; i++){
+    for(let i=0; i<draggables.length; i++){
       draggables[i].addEventListener('mousedown', function(event){
-        var x = event.pageX - event.currentTarget.offsetLeft;
-        var y = event.pageY - event.currentTarget.offsetTop - window.scrollY;
-        var elem = event.currentTarget;
-        elem.style.zIndex = ++maxz;
+        let x = event.pageX - event.currentTarget.offsetLeft;
+        let y = event.pageY - event.currentTarget.offsetTop - window.scrollY;
+        let elem = event.currentTarget;
+        elem.style.transform = "scale(" + trial.scale_factor + "," + trial.scale_factor + ")";
+        let mousemoveevent = function(e){
+          cur_in = inside_ellipse(e.clientX - x, e.clientY - y, 
+              trial.sort_area_width*.5 - trial.stim_width*.5, trial.sort_area_height*.5 - trial.stim_height*.5, 
+              trial.sort_area_width*.5, trial.sort_area_height*.5,
+              trial.sort_area_shape == "square");
+          elem.style.top =  Math.min(trial.sort_area_height - trial.stim_height*.5, Math.max(- trial.stim_height*.5, (e.clientY - y))) + 'px';
+          elem.style.left = Math.min(trial.sort_area_width*1.5  - trial.stim_width,  Math.max(-trial.sort_area_width*.5, (e.clientX - x)))+ 'px';
+          
+          // modify border while items is being moved
+          if (cur_in) {
+            border.style.borderColor = "#a1d99b";
+            border.style.background = "None";
+          } else {
+            border.style.borderColor = "#fc9272";
+            border.style.background = "None";
+          }
+          
+          // replace in overall array, grab idx from item id
+          inside.splice(elem.id, true, cur_in)
 
-        var mousemoveevent = function(e){
-          elem.style.top =  Math.min(trial.sort_area_height - trial.stim_height, Math.max(0,(e.clientY - y))) + 'px';
-          elem.style.left = Math.min(trial.sort_area_width  - trial.stim_width,  Math.max(0,(e.clientX - x))) + 'px';
+          // modify text and background if all items are inside
+          if (inside.every(Boolean)) {
+            border.style.background = "#a1d99b";
+            button.style.display = "inline-block";
+            display_element.querySelector("#jspsych-free-sort-counter").innerHTML = "All items placed. Feel free to reposition any item if necessary. Otherwise, click here to "
+          } else {
+            border.style.background = "none";
+            button.style.display = "none";
+            if ( (inside.length - inside.filter(Boolean).length) > 1 ) {
+              display_element.querySelector("#jspsych-free-sort-counter").innerHTML = "You still need to place " + (inside.length - inside.filter(Boolean).length) + " items inside the arena."
+            } else {
+              display_element.querySelector("#jspsych-free-sort-counter").innerHTML = "You still need to place " + (inside.length - inside.filter(Boolean).length) + " item inside the arena."
+            }
+          }
         }
         document.addEventListener('mousemove', mousemoveevent);
 
         var mouseupevent = function(e){
           document.removeEventListener('mousemove', mousemoveevent);
+          elem.style.transform = "scale(1, 1)";
+          if (inside.every(Boolean)) {
+            border.style.background = "#a1d99b";
+            border.style.borderColor = "#a1d99b";
+          } else {
+            border.style.background = "none";
+            border.style.borderColor = "#fc9272";
+          }
           moves.push({
             "src": elem.dataset.src,
             "x": elem.offsetLeft,
@@ -148,47 +264,86 @@ jsPsych.plugins['free-sort'] = (function() {
       });
     }
 
-    display_element.querySelector('#jspsych-free-sort-done-btn').addEventListener('click', function(){
+    display_element.querySelector('#jspsych-free-sort-done-btn').addEventListener('click', function(){      
+      if (inside.every(Boolean)) {
+        const end_time = performance.now();
+        const rt = end_time - start_time;
+        // gather data
+        const items = display_element.querySelectorAll('.jspsych-free-sort-draggable');
+        // get final position of all items
+        let final_locations = [];
+        for(let i=0; i<items.length; i++){
+          final_locations.push({
+            "src": items[i].dataset.src,
+            "x": parseInt(items[i].style.left),
+            "y": parseInt(items[i].style.top)
+          });
+        }
 
-      var end_time = performance.now();
-      var rt = end_time - start_time;
-      // gather data
-      // get final position of all objects
-      var final_locations = [];
-      var matches = display_element.querySelectorAll('.jspsych-free-sort-draggable');
-      for(var i=0; i<matches.length; i++){
-        final_locations.push({
-          "src": matches[i].dataset.src,
-          "x": parseInt(matches[i].style.left),
-          "y": parseInt(matches[i].style.top)
-        });
+        const trial_data = {
+          "init_locations": JSON.stringify(init_locations),
+          "moves": JSON.stringify(moves),
+          "final_locations": JSON.stringify(final_locations),
+          "rt": rt
+        };
+        
+        // advance to next part
+        display_element.innerHTML = '';
+        jsPsych.finishTrial(trial_data);
       }
-
-      var trial_data = {
-        "init_locations": JSON.stringify(init_locations),
-        "moves": JSON.stringify(moves),
-        "final_locations": JSON.stringify(final_locations),
-        "rt": rt
-      };
-
-      // advance to next part
-      display_element.innerHTML = '';
-      jsPsych.finishTrial(trial_data);
     });
-
   };
 
   // helper functions
 
-  function random_coordinate(max_width, max_height) {
-    var rnd_x = Math.floor(Math.random() * (max_width - 1));
-    var rnd_y = Math.floor(Math.random() * (max_height - 1));
+  function shuffle(array) {
+    // define three variables
+    let cur_idx = array.length, tmp_val, rand_idx;
 
+    // While there remain elements to shuffle...
+    while (0 !== cur_idx) {
+      // Pick a remaining element...
+      rand_idx = Math.floor(Math.random() * cur_idx);
+      cur_idx -= 1;
+
+      // And swap it with the current element.
+      tmp_val = array[cur_idx];
+      array[cur_idx] = array[rand_idx];
+      array[rand_idx] = tmp_val;
+    }
+    return array;
+  }
+  
+  function make_arr(startValue, stopValue, cardinality) {
+    const step = (stopValue - startValue) / (cardinality - 1);
+    let arr = [];
+    for (let i = 0; i < cardinality; i++) {
+      arr.push(startValue + (step * i));
+    }
+    return arr;
+  }
+
+  function inside_ellipse(x, y, x0, y0, rx, ry, square=false) {
+    const results = [];
+    if (square) {
+      result = ( Math.abs(x - x0) <= rx ) && ( Math.abs(y - y0) <= ry )
+    } else {
+      result = (( x - x0 ) * ( x - x0 )) * (ry * ry) + ((y - y0) * ( y - y0 )) * ( rx * rx ) <= ( (rx * rx) * (ry * ry) )
+    }
+    return result 
+  }
+
+  /* 
+  un-used functions (that might be useful for something else)
+
+  function random_coordinate(max_width, max_height) {
+    const rnd_x = Math.floor(Math.random() * (max_width - 1));
+    const rnd_y = Math.floor(Math.random() * (max_height - 1));
     return {
       x: rnd_x,
       y: rnd_y
     };
   }
-
+  */
   return plugin;
 })();