diff --git a/hydra-test.js b/hydra-test.js
new file mode 100644
index 0000000..9587d1c
--- /dev/null
+++ b/hydra-test.js
@@ -0,0 +1,142 @@
+let hydra_test_map = {
+    ":": 2,
+    "[": 1,
+    "]": 0,
+}
+
+let hydra_test_compare = (seq1, seq2) => {
+   if(seq1.length===0){
+      if(seq2.length===0) return 0
+      else return -1
+   }else{
+      if(seq2.length===0) return 1
+      else{
+          if (hydra_test_map[seq1[0]] === hydra_test_map[seq2[0]]) {
+            return hydra_test_compare(seq1.slice(1),seq2.slice(1))
+          }
+          return Math.sign(hydra_test_map[seq1[0]] - hydra_test_map[seq2[0]]);
+      }
+   }
+};
+
+let matching_parenthesis_close = (str, index, open, close) => {
+    let openIndex = index;
+    let counter = 1;
+    while (counter > 0 && openIndex >= 0) {
+        openIndex--;
+        let c = str[openIndex];
+        if (c === close) {
+            counter++;
+        }
+        if (c === open) {
+            counter--;
+        }
+    }
+    return openIndex;
+}
+
+{
+    let lim = (FSterm)=>{
+        if(FSterm == 0)
+        {
+            return "[[]]";
+        }
+        else
+        {
+            let result = "[[!]]";
+            for(let i = 0; i < FSterm; i++)
+            {
+                result = result.replace("!", "[:!]");
+            }
+            return result.replace("!","");
+        }
+    };
+    let hydra_test = (str, FSterm) => {
+        let indexopen = str.lastIndexOf("[");
+        let indexclose = indexopen + 1;
+        if(str[indexclose] === "]") {
+            let outerclose = indexopen + 2;
+            let outeropen = matching_parenthesis_close(str, outerclose, "[", "]");
+            let repeat = str.slice(outeropen, indexopen) + str.slice(indexclose + 1, outerclose + 1) + "!";
+            let result = str.slice(0, outeropen) + "!" + str.slice(outerclose + 1);
+            for (let i = 0; i < FSterm; i++) {
+                result = result.replace("!", repeat);
+            }
+            return result.replace("!", "");
+        } else if (str[indexclose] === ":") {
+            let indexclose = indexopen + 2;
+            let outerclose = indexopen + 3;
+            let outeropen = matching_parenthesis_close(str, outerclose, "[", "]");
+            let innerclose = indexclose;
+            let inneropen = indexopen;
+            let innerclose2 = innerclose;
+            let inneropen2 = inneropen;
+            let breakout = false;
+            for (let i = 0; i < 3; i++) {
+                while (hydra_test_compare(str.slice(inneropen, innerclose + 1), str.slice(outeropen, outerclose + 1)) <= 0) {
+                    outerclose = outerclose + 1;
+                    outeropen = matching_parenthesis_close(str, outerclose, "[", "]");
+                    
+                    if (outerclose >= str.length || (i > 3 && hydra_test_compare(str.slice(inneropen2, innerclose2 + 1), str.slice(outeropen, outerclose + 1)) > 0) || (hydra_test_compare("[[:]]", str.slice(outeropen, outerclose + 1)) > 0)) {
+                        outerclose = outerclose - 1;
+                        outeropen = outeropen + 1;
+                        breakout = true;
+                        break;
+                    }
+                }
+                if (breakout) {
+                    break;
+                }
+                innerclose = outerclose;
+                inneropen = outeropen;
+                if (i === 0) {
+                    innerclose2 = innerclose;
+                    inneropen2 = inneropen;
+                }
+            }
+            if (!breakout) {
+                indexclose = innerclose2;
+                indexopen = inneropen2;
+                outerclose = outerclose-1;
+                outeropen = matching_parenthesis_close(str, outerclose, "[", "]");
+            }
+            let repeat = str.slice(outeropen, indexopen) + "!" + str.slice(indexclose + 1, outerclose + 1);
+            let result = str.slice(0, outeropen) + "!" + str.slice(outerclose + 1);
+            for (let i = 0; i < FSterm; i++) {
+                result = result.replace("!", repeat);
+            }
+            return result.replace("!", "");
+        }
+    };
+    let display = (str) => {
+        for (let i = str.length - 1; i >= 0; i--) {
+            if (str[i] == "]" && str[matching_parenthesis_close(str, i, "[", "]") + 1] == ":") {
+                str = str.slice(0, i) + ">" + str.slice(i+1);
+            }
+        }
+        return str.replaceAll("[:", "<");
+    }
+register.push({
+   id:'hydra_test',
+   name:'hydra_test',
+   display:display,
+   able:(x) => (x.length >= 2 && x[x.length-2]!=="["),
+   compare:hydra_test_compare,
+   FS:(()=>{
+      var data={};
+      return (seq,FSterm)=>{
+        if(!seq.length) return ""
+        var datakey=seq;
+        if(datakey==='Limit') return lim(FSterm);
+        if(seq[seq.length-2]==="[") return seq.substring(0,seq.length-2);
+        if(!data[datakey]) data[datakey] = [];
+        else if(data[datakey][FSterm]!==undefined) return data[datakey][FSterm];
+        return data[datakey][FSterm] = hydra_test(seq,FSterm);
+      };
+   })(),
+   init:()=>([
+      {expr:"Limit",low:[""],subitems:[]}
+      ,{expr:"",low:[""],subitems:[]}
+   ])
+})
+}
\ No newline at end of file
diff --git a/index.html b/index.html
index 69af88a..3131722 100644
--- a/index.html
+++ b/index.html
@@ -55,6 +55,8 @@
 <script src="LON.js"></script>
 <script src="HSPN.js"></script>
 <script src="cOCF.js"></script>
+<!--<script src="ingrown.js"></script>-->
+<script src="hydra-test.js"></script>
 <script src="framework.js"></script>
 </body>
 </html>
\ No newline at end of file
diff --git a/ingrown.js b/ingrown.js
new file mode 100644
index 0000000..b1d4db5
--- /dev/null
+++ b/ingrown.js
@@ -0,0 +1,220 @@
+let ingrown_compare = (seq1,seq2)=>{
+   if(seq1.length===0){
+      if(seq2.length===0) return 0
+      else return -1
+   }else{
+      if(seq2.length===0) return 1
+      else{
+        if(seq1[0][0] < seq2[0][0]) {
+            let seq3 = [];
+            let diff = seq2[0][0] - seq1[0][0];
+            for(let i = 0; i < seq2.length; i++) {
+                seq3.push([]);
+                for(let j = 0; j < seq2[i].length; j++) {
+                    if(seq2[i][j] > diff) {
+                        seq3[i].push(seq2[i][j] - diff);
+                    } else {
+                        seq3[i].push(0);
+                    }
+                }
+            }
+            seq2 = seq3;
+        }
+         for(let i = 0; i < Math.max(seq1[0].length,seq2[0].length); i++)
+         {
+             if(!seq1[0][i] && !seq2[0][i]) break;
+             else if(!seq1[0][i] && seq2[0][i]) return -1;
+             else if(seq1[0][i] && !seq2[0][i]) return 1;
+             else if(seq1[0][i]<seq2[0][i]) return -1;
+             else if(seq1[0][i]>seq2[0][i]) return 1;
+         }
+         return ingrown_compare(seq1.slice(1),seq2.slice(1))
+      }
+   }
+};
+
+let ingrownSvg = (seq) => {
+    
+    var svg = document.createElementNS("http://www.w3.org/2000/svg", "svg");
+    var path1 = document.createElementNS("http://www.w3.org/2000/svg", 'path');
+    var path2 = document.createElementNS("http://www.w3.org/2000/svg", 'path');
+    
+    svg.setAttribute("aria-hidden","true");
+    
+    
+    var svgElements = subSvg(seq,0,0,0,[]).svgElements;
+    
+    for(let i in svgElements) {
+        svg.appendChild(svgElements[i]);
+    }
+    document.body.appendChild(svg);
+    
+    let bbox = svg.getBBox({stroke:true});
+
+    svg.remove();
+    
+    // Set the viewport with these bounds
+    svg.setAttribute("viewBox", `${bbox.x-10} ${bbox.y-10} ${bbox.width+20} ${bbox.height+20}`);
+    svg.setAttribute('width', `${bbox.width+10}`);
+    svg.setAttribute('height', `${bbox.height+10}`);
+    
+    return svg.outerHTML;
+}
+
+let subSvg = (seq,num,x,y,prev,toggleWidth) => {
+    if(seq.length == 0) {
+        return {width: 20, svgElements: []};
+    }
+    let totalWidth = 0;
+    let result = [];
+    for(let i = seq.length-1; i >= 0; i--) {
+        if(seq[i][0] == num) {
+            let svgElement = document.createElementNS("http://www.w3.org/2000/svg","circle");
+            if(seq[i][1] && seq[i][1] > 0 && totalWidth == 0) {
+                if(!toggleWidth) {
+                    totalWidth = 20;
+                }
+                toggleWidth = !toggleWidth;
+            } else {
+                toggleWidth = false;
+            }
+            svgElement.className.baseVal = "node";
+            svgElement.cx.baseVal.value = x+totalWidth;
+            svgElement.cy.baseVal.value = y;
+            svgElement.r.baseVal.value = 5;
+            svgElement.style.fill = 'rgb(0,0,0)';
+            result.push(svgElement);
+            for(let j = 0; j < seq[i].length; j++) {
+                if(seq[i][j] > 0) {
+                    let svgElement2 = document.createElementNS("http://www.w3.org/2000/svg","line");
+                    svgElement2.className.baseVal = "segment";
+                    svgElement2.x1.baseVal.value = prev[seq[i][j]-1][0];
+                    svgElement2.y1.baseVal.value = prev[seq[i][j]-1][1];
+                    svgElement2.x2.baseVal.value = x+totalWidth;
+                    svgElement2.y2.baseVal.value = y;
+                    svgElement2.style.stroke = 'rgb(0,0,0)';
+                    svgElement2.style["stroke-width"] = '1.2px';
+                    svgElement2.style["stroke-linecap"] = 'round';
+                    svgElement2.style["stroke-linejoin"] = 'round';
+                    result.push(svgElement2);
+                } else {
+                    break;
+                }
+            }
+            let sub = subSvg(getSubtree(seq,i),num+1,x+totalWidth,y-40/(num+1),prev.concat([[x+totalWidth,y]]),toggleWidth);
+            result = result.concat(sub.svgElements);
+            totalWidth += sub.width;
+        }
+    }
+    return {width: totalWidth, svgElements: result};
+}
+
+let getSubtree = (seq, i) => {
+    let j = i+1;
+    for(j; j < seq.length; j++) {
+        if(seq[j][0] <= seq[i][0]) {
+            break;
+        }
+    }
+    return seq.slice(i+1,j);
+}
+
+let getSubtree2 = (seq, i) => {
+    let j = i+1;
+    for(j; j < seq.length; j++) {
+        if(seq[j][0] <= seq[i][0]) {
+            break;
+        }
+    }
+    return seq.slice(i,j);
+}
+
+let ingrown_display = expr=>''+expr==='Infinity'?'Limit': ingrownSvg(expr)+expr.map(col => col.toString().split(',0')[0]).join(' ');
+let ingrown_display2 = expr=>''+expr==='Infinity'?'Limit': expr.map(col => col.toString().split(',0')[0]).join(' ');
+let ingrown_limit = seq=>seq.length>0&&seq[seq.length-1][0]>0;
+
+{
+    let lim = (FSterm)=>{
+        if(FSterm == 0)
+        {
+            return [[0]];
+        }
+        else
+        {
+            let arr = [];
+            for(let i = FSterm; i >= 0; i--)
+            {
+                arr.push(i);
+            }
+            return lim(FSterm-1).concat([arr]);
+        }
+    };
+    let ingrown = (seq,FSterm)=>{
+        let seq2 = seq.slice(0,seq.length-1);
+        if(FSterm === 0)
+        {
+            return seq2;
+        }
+        if(seq[seq.length-1][1]===0)
+        {
+            let index = seq.findLastIndex((x) => x[0] === seq[seq.length-1][0]-1);
+            return ingrown(seq,FSterm-1).concat(seq2.slice(index));
+        }
+        else
+        {
+            let subindex = seq[seq.length-1].findLastIndex((x) => x !== 0);
+            let diffTotal = seq[seq.length-1][subindex] + subindex - 1;
+            let index = seq.findLastIndex((x) => x[0] === diffTotal - 1);
+            let index2 = seq.findLastIndex((x) => x[0] === diffTotal);
+            if(ingrown_compare(getSubtree2(seq,index),getSubtree2(seq,index2)) === -1) {
+                index = index2-1;
+            }
+            let repeat = seq2.slice(index);
+            repeat.shift();
+            return ingrown(seq,FSterm-1).concat(increment(repeat,FSterm,seq[seq.length-1][0] - diffTotal,seq[seq.length-1]));
+        }
+    };
+    let increment = (seq,FSterm,add,last)=>{
+        return seq.map(x => x.map(y => increment2(y,FSterm,add,last)));
+    }
+    let increment2 = (num,FSterm,add,last)=>{
+        for(let i = 0; i < FSterm; i++)
+        {
+            if (num < last.findLast((x) => x !== 0)) {
+                break;
+            }
+            if(last.indexOf(num) > 0 && num > 0 && num < last[0] - add) {
+                num = last[last.indexOf(num)-1];
+            } else if (num < last[0] - add) {
+                let diff = num - last.find((z) => z < num);
+                num = last.findLast((z) => z > num) + diff;
+            } else {
+                num = num + add;
+            }
+        }
+        return num;
+    }
+register.push({
+   id:'ingrown',
+   name:'Ingrown hydra',
+   display:ingrown_display,
+   able:ingrown_limit,
+   compare:ingrown_compare,
+   FS:(()=>{
+      var data={};
+      return (seq,FSterm)=>{
+        if(!seq.length) return []
+        var datakey=''+seq;
+        if(datakey==='Infinity') return lim(FSterm);
+        if(seq[seq.length-1][0]===0) return seq.slice(0,seq.length-1);
+        if(!data[datakey]) data[datakey] = [];
+        else if(data[datakey][FSterm]!==undefined) return data[datakey][FSterm];
+        return data[datakey][FSterm] = ingrown(seq,FSterm);
+      };
+   })(),
+   init:()=>([
+      {expr:[[[Infinity]]],low:[[]],subitems:[]}
+      ,{expr:[],low:[[]],subitems:[]}
+   ])
+})
+}
\ No newline at end of file