diff --git a/data/scenarios/Challenges/_pied-piper/rat.sw b/data/scenarios/Challenges/_pied-piper/rat.sw
index c6e744a59..0cfa18b78 100644
--- a/data/scenarios/Challenges/_pied-piper/rat.sw
+++ b/data/scenarios/Challenges/_pied-piper/rat.sw
@@ -1,4 +1,46 @@
+def goFoodDir = \f. \r.
+    // say "in goFoodDir";
+    let d = fst r in
+    if (d == down) {
+        foodHere <- ishere "oats";
+        if foodHere {
+            grab; return ()
+        } {};
+        f;
+        return ()
+    } {
+        turn d;
+
+        // An obstruction might arise after
+        // navigation direction is determined
+        // but before we move.
+        try {
+            move;
+        } {};
+        f;
+    }
+    end;
+
+def goHomeDir = \f. \r.
+    // say "in goHomeDir";
+    let d = fst r in
+    if (d == down) {
+        return ()
+    } {
+        turn d;
+
+        // An obstruction might arise after
+        // navigation direction is determined
+        // but before we move.
+        try {
+            move;
+        } {};
+        f;
+    }
+    end;
+
 def findGoodDirection =
+    // say "in findGoodDirection";
     isBlocked <- blocked;
     if isBlocked {
         turn left;
@@ -23,15 +65,45 @@ def pauseAtRandom =
     } {}
     end;
 
-def doMovement =
+def returnHome = \homeLoc.
+    // say "in returnHome";
+    nextDir <- path (inL ()) (inL homeLoc);
+    case nextDir return $ goHomeDir $ returnHome homeLoc;
+    end;
+
+def pursueFood = \hadSensedFood. \homeLoc.
+    // say $ "in pursueFood. hadSensedFood? " ++ format hadSensedFood;
+    nextDir <- path (inR 5) (inR "oats");
+    case nextDir (\_. if hadSensedFood {returnHome homeLoc} {return ()}) $
+        goFoodDir $ pursueFood true homeLoc;
+    end;
+
+def checkExpireSelf =
+    loc <- whereami;
+    if (snd loc > 6) {selfdestruct} {};
+    end;
+
+def doMovement = \startLoc.
+    // say "in doMovement";
+    checkExpireSelf;
+
     findGoodDirection;
     moveUntilBlocked;
-    pauseAtRandom
+    pauseAtRandom;
+    pursueFood false startLoc;
     end;
 
-def go =
-    doMovement;
-    go;
+/** Loop */
+def go = \startLoc.
+    doMovement startLoc;
+    go startLoc;
     end;
 
-go;
\ No newline at end of file
+startLoc <- whereami;
+// let shouldDestruct = !(snd startLoc == -17 && fst startLoc < 19) in
+let shouldDestruct = false in
+if shouldDestruct {
+    selfdestruct;
+} {
+    go startLoc;
+}
diff --git a/data/scenarios/Challenges/_pied-piper/solution.sw b/data/scenarios/Challenges/_pied-piper/solution.sw
index 065404d56..abefbe0ab 100644
--- a/data/scenarios/Challenges/_pied-piper/solution.sw
+++ b/data/scenarios/Challenges/_pied-piper/solution.sw
@@ -1,8 +1,15 @@
+def doN = \n. \f. if (n > 0) {f; doN (n - 1) f} {}; end;
+
+def makeOatsTrail =
+  place "oats";
+  doN 4 move;
+  end;
+
 def go =
-  place "tree";
-  move; move;
-  // place "oats";
+  doN 5 makeOatsTrail;
+  turn back;
+  doN (5*4) move;
+  turn back;
   end;
 
-wait 10;
 go;
\ No newline at end of file
diff --git a/data/scenarios/Challenges/pied-piper.yaml b/data/scenarios/Challenges/pied-piper.yaml
index 5a831d6a8..a7634d992 100644
--- a/data/scenarios/Challenges/pied-piper.yaml
+++ b/data/scenarios/Challenges/pied-piper.yaml
@@ -17,8 +17,8 @@ terrains:
       Wooden raised path
 robots:
   - name: base
-    loc: [18, -22]
-    dir: north
+    loc: [19, 7]
+    dir: south
     devices:
       - 3D printer
       - ADT calculator
@@ -26,19 +26,24 @@ robots:
       - branch predictor
       - clock
       - comparator
+      - compass
       - counter
       - dictionary
       - grabber
+      - hearing aid
       - lambda
       - logger
       - net
       - scanner
       - strange loop
       - string
+      - treads
       - workbench
     inventory:
-      - [50, oats]
-      - [50, tree]
+      - [200, oats]
+    walkable:
+      never:
+        - door
   - name: rat
     system: true
     dir: west
@@ -49,16 +54,6 @@ robots:
       - logger
     program: |
       run "scenarios/Challenges/_pied-piper/rat.sw"
-  - name: helper
-    loc: [0, 10]
-    system: true
-    dir: west
-    display:
-      invisible: false
-    devices:
-      - logger
-    program: |
-      noop;
 objectives:
   - goal:
       - Rats have infested the village dwellings. Clear them out!
@@ -72,10 +67,17 @@ solution: |
 entities:
   - name: door
     display:
-      char: 'X'
+      char: 'D'
     description:
       - door
     properties: [known]
+  - name: wall
+    display:
+      char: 'W'
+      attr: wood
+    description:
+      - wall
+    properties: [known, unwalkable]
   - name: oats
     display:
       attr: oats
@@ -93,7 +95,7 @@ world:
       structure:
         palette:
           'd': [stone, door]
-          'x': [stone, boulder]
+          'x': [stone, wall]
           '.': [stone]
           'r': [stone, erase, rat]
         map: |
@@ -150,8 +152,8 @@ world:
     , mask (y > -37 && y < -32) {stone}
     ]
   map: |
-    ....bbbb..
-    ....bbbb..
-    ....bbbb..
-    ....bbbb..
-    ....bbbb..
+    ....bbbb
+    ....bbbb
+    ....bbbb
+    ....bbbb
+    ....bbbb