diff --git a/index.html b/index.html
old mode 100755
new mode 100644
index 0ccf3d9..ae4915c
--- a/index.html
+++ b/index.html
@@ -42,6 +42,7 @@
                 background <input type='text' value='#f5f5f5' class='settinginput' id='bgcolor_in' onchange="applystyle();" placeholder='#f5f5f5' maxlength='12'/>
               , text <input type='text' value='black' class='settinginput' id='textcolor_in' onchange="applystyle();"  placeholder='#000' maxlength='12'/>
               , links <input type='text' value='#004411' class='settinginput' id='linkscolor_in' onchange="applystyle();"  placeholder='#004411' maxlength='12'/>
+              , goal (ms) <input type='number' value = 0 class='settinginput' id='goal_in' onchange="applygoal();" placeholder=0 max=10000 title="Goal in ms to beat in each alg solve. If you beat the goal, the probability of getting the same alg will decrease. Otherwise it will increase. Leave this at 0 (default) to keep every selected alg with the same probability."/> (0 or empty to ignore dynamic weights)
               <br>
 			<span id="last_scramble">
 			Any questions/suggestions/bugs reports - post in <a href="https://www.speedsolving.com/forum/threads/oll-trainer.66924/" target="_blank" class="settings">this thread</a>
diff --git a/scripts/algsinfo.js b/scripts/algsinfo.js
index fab7265..f014fa4 100755
--- a/scripts/algsinfo.js
+++ b/scripts/algsinfo.js
@@ -1,5 +1,9 @@
 var selCases = [];
 
+var algsOrder = [];
+
+var selCasesWeights = [];
+
 var algsGroups = {
     "All Edges Oriented Correctly" : [26, 27, 21, 22, 24, 25, 23],
     "T-Shapes" : [33, 45],
@@ -17,6 +21,10 @@ var algsGroups = {
     "No Edges Flipped Correctly" : [1,2,3,4,18,19,17,20],
 };
 
+for (i in algsGroups) {
+    algsOrder = algsOrder.concat(algsGroups[i]);
+}
+
 var algsInfo = {
     1: {
         "name": "Runway",
diff --git a/scripts/saveload.js b/scripts/saveload.js
old mode 100755
new mode 100644
index ad23ceb..3b062d4
--- a/scripts/saveload.js
+++ b/scripts/saveload.js
@@ -27,7 +27,13 @@ function loadLocal(name, defaultValue) {
     }
 }
 
+function initializeSelCasesWeights() {
+    window.selCasesWeights = new Array(window.selCases.length).fill(1);
+}
+
 function saveSelection() {
+    // we re-initialize the weights on selection change (save)
+    initializeSelCasesWeights();
     return saveLocal('ollSelection', JSON.stringify(window.selCases));
 }
 
diff --git a/scripts/timer.js b/scripts/timer.js
old mode 100755
new mode 100644
index 5d08fc8..89ccc2f
--- a/scripts/timer.js
+++ b/scripts/timer.js
@@ -4,6 +4,7 @@ if (timesArray == null) // todo fix when figure out why JSON.parse("[]") returns
     timesArray = [];
 var lastScramble = "";
 var lastCase = 0;
+var goal = 0;
 
 displayStats(); // after loading
 
@@ -29,6 +30,31 @@ function randomElement(arr)
     return arr[Math.floor(Math.random()*arr.length)];
 }
 
+// https://stackoverflow.com/a/55671924
+function randomWeightedElement(items, weights) {
+    var i;
+    var _w = weights.slice(); // don't want to modify the original weights
+
+    for (i = 1; i < _w.length; i++)
+        _w[i] += _w[i - 1];
+    
+    var random = Math.random() * _w[_w.length - 1];
+    
+    for (i = 0; i < _w.length; i++)
+        if (_w[i] > random)
+            break;
+    
+    return items[i];
+}
+
+function updateSelectedWeights(ms)
+{
+    if (isNaN(window.goal) || window.goal == 0) return;
+    const index = window.selCases.indexOf(window.lastCase);
+    if (ms > window.goal) window.selCasesWeights[index] *= 2;
+    else window.selCasesWeights[index] /= 2;
+}
+
 function confirmUnsel(i) {
     if (confirm("Do you want to unselect this case?")) {
         var index = window.selCases.indexOf(i);
@@ -62,7 +88,7 @@ function generateScramble()
     // get random case
     var caseNum = 0;
     if (recapArray.length == 0) { // train
-        caseNum = randomElement(window.selCases);
+        caseNum = randomWeightedElement(window.selCases, window.selCasesWeights);
     } else { // recap
         // select the case
         caseNum = randomElement(window.recapArray);
@@ -348,7 +374,9 @@ function escapeHtml(text) {
 function appendStats()
 {
     // assuming the time can be grabbed from timer label, and the case - window.lastCase
-    window.timesArray.push(makeResultInstance());
+    var mri = makeResultInstance();
+    window.timesArray.push(mri);
+    updateSelectedWeights(mri.ms);
     displayStats();
 }
 
@@ -389,6 +417,7 @@ function confirmClear()
 {
     if (confirm("Are you sure you want to clear session?")) {
         window.timesArray = [];
+        initializeSelCasesWeights();
         document.getElementById('infoHeader').innerHTML = ('')
         displayStats();
     }
@@ -453,7 +482,10 @@ function displayStats()
         }
 
         var keys = Object.keys(resultsByCase);
-        keys.sort();
+        keys.sort(function(a, b) {
+            //return parseInt(a) - parseInt(b); // old simple fix numerical order
+            return algsOrder.indexOf(a) - algsOrder.indexOf(b); // new algsinfo ordering
+        });
 
         var s = "";
         // allocate them inside times span
@@ -462,6 +494,8 @@ function displayStats()
             var timesString = "";
             var meanForCase = 0.0;
             var i = 0;
+            if (!isNaN(window.goal) && window.goal > 0) 
+                timesString += "[weight: " + window.selCasesWeights[window.selCases.indexOf(parseInt(oll))] + "] ";
             for (; i < resultsByCase[oll].length; i++)
             {
                 timesString += makeHtmlDisplayableTime(resultsByCase[oll][i]);
@@ -570,6 +604,12 @@ function resetStyle(dark) {
     savestyle();
 }
 
+function applygoal() {
+    //window.goal = document.getElementById("goal_in").value;
+    window.goal = document.querySelector('#goal_in').valueAsNumber;
+    displayStats();
+}
+
 // add key listeners to blur settings inputs
 var inputs = document.getElementsByClassName("settinginput");
 Array.prototype.forEach.call(inputs, function(el) {