diff --git a/examples/fasteffekt/list.effekt b/examples/fasteffekt/list.effekt
index f194ea3e6..2a2ac3ecc 100644
--- a/examples/fasteffekt/list.effekt
+++ b/examples/fasteffekt/list.effekt
@@ -1,9 +1,20 @@
+import examples/fasteffekt/benchmark
+
+
 // class Element {
 //   constructor(v) {
 //     this.val = v;
 //     this.next = null;
 //   }
+record Element (
+    value: Int, child: Option[Element]
+)
 
+def length(element: Option[Element]): Int = 
+    element match {
+        case None() => return 0;
+        case Some(Element(value, child)) => return 1 + length(child) 
+    }
 //   length() {
 //     if (this.next === null) {
 //       return 1;
@@ -12,62 +23,92 @@
 //   }
 // }
 
-import examples/fasteffekt/benchmark
+def isShorterThan(x: Option[Element], y: Option[Element]): Boolean = {
+    var xTail:Option[Element] = x;
+    var yTail:Option[Element] = y;
+    var run = true;
+    var bigger = false;
+    while (run) {
+        (xTail,yTail) match {
+            case (_, None()) => run = false; bigger = false;
+            case (None(), _) => run =false; bigger = true;
+            case (Some(xx),Some(yy)) => xTail = xx.child; yTail = yy.child;
+        }
+    }
+    return bigger;
 
-def List() = {
-    println("run list benchmark");
+//     while (yTail !== null) {
+//       if (xTail === null) { return true; }
+//       xTail = xTail.next;
+//       yTail = yTail.next;
+//     }
+//     return false;
 
-    def benchmark(): Int = {
-        var result = 0;
-        // arr = emptyArray[Int](6);
-
-        // each(0,arr.size()){ i =>
-        //     put(arr,i, 1);  
-        // }
-        // permute(6);
-        return count;
+}
+
+def makeList(lenght: Int): Option[Element] = {
+    return if(lenght == 0) {
+        None()
+    } else {
+        Some(Element(0, makeList(lenght-1)))
+    }
+}
+
+  //no idea what that function does.
+    def tail(x: Option[Element], y: Option[Element], z: Option[Element]): Option[Element] = {
+        if (y.isShorterThan(x)) {
+            (x,y,z) match {
+                case (Some(xx),Some(yy),Some(zz)) => 
+                    //compiler KNOWS that xx,yy,zz are not None() => can access children.
+
+                    //all children have type Option[Element]
+                    val xChild = xx.child;
+                    val yChild = yy.child;
+                    val zChild = zz.child;
+
+                    val xxx = tail(xChild, y, z);
+                    val yyy = tail(yChild, z, x);
+                    val zzz = tail(zChild, x, y);
+                    tail(
+                        xxx,
+                        yyy,
+                        zzz
+                    )
+                case _ => panic("oh no!");
+            }
+        } else {
+            z;
+        }
     }
 
-    def makeList(lenght: int) = {
+def List() = {
+    println("run list benchmark");
 
+    def benchmark(): Int = {
+        val result = 
+        tail(
+            makeList(15),
+            makeList(10),
+            makeList(6)
+        );
+        length(result);
     }
+    
+    
 
     def verifyResult(result: Int): Boolean = {
         return result == 10;
     }
 
-    return 0;
+    return innerBenchmarkLoop(1){benchmark}{verifyResult};
 }
-// class List extends Benchmark {
-//   benchmark() {
-//     const result = this.tail(
-//       this.makeList(15),
-//       this.makeList(10),
-//       this.makeList(6)
-//     );
-//     return result.length();
-//   }
 
-//   makeList(length) {
-//     if (length === 0) {
-//       return null;
-//     }
-//     const e = new Element(length);
-//     e.next = this.makeList(length - 1);
-//     return e;
-//   }
+def main() = {
+    List();
+}
+// class List extends Benchmark {
 
-//   isShorterThan(x, y) {
-//     let xTail = x;
-//     let yTail = y;
 
-//     while (yTail !== null) {
-//       if (xTail === null) { return true; }
-//       xTail = xTail.next;
-//       yTail = yTail.next;
-//     }
-//     return false;
-//   }
 
 //   tail(x, y, z) {
 //     if (this.isShorterThan(y, x)) {