Better motivated puzzle

data/scenarios/Challenges/_dna/solution.sw

@@ -1,5 +1,53 @@
 def doN = \n. \f. if (n > 0) {f; doN (n - 1) f} {}; end;
 
+def getBaseForNumber = \n.
+    if (n == 0) {
+        "guanine";
+    } {
+        if (n == 1) {
+            "cytosine";
+        } {
+            if (n == 2) {
+                "adenine";
+            } {
+                "thymine";
+            };
+        };
+    };
+    end;
+
+def getNumberForBase = \n.
+    if (n == "guanine") {
+        0;
+    } {
+        if (n == "cytosine") {
+            1;
+        } {
+            if (n == "adenine") {
+                2;
+            } {
+                3;
+            };
+        };
+    };
+    end;
+
+def getComplementNumber = \n.
+    if (n == 0) {
+        1;
+    } {
+        if (n == 1) {
+            0;
+        } {
+            if (n == 2) {
+                3;
+            } {
+                2;
+            };
+        };
+    };
+    end;
+
 def waitWhileHere = \item.
     stillHere <- ishere item;
     if stillHere {
@@ -24,12 +72,16 @@ def moveToPattern =
     turn right;
     doN 2 move;
     turn right;
-    doN 5 move;
+    doN 4 move;
+    turn right;
+    move;
+    turn left;
+    move;
     end;
 
 def moveToOtherRow =
     turn right;
-    doN 9 move;
+    doN 8 move;
     turn right;
     move;
     end;
@@ -39,13 +91,22 @@ def waitForItem : Dir -> Cmd Text = \d.
     case item (\_. waitForItem d) return;
     end;
 
+
+def placeComplementOf = \item.
+    let baseNumber = getNumberForBase item in
+    let complementNumber = getComplementNumber baseNumber in
+    let newItem = getBaseForNumber complementNumber in
+    place newItem;
+    end;
+
 /**
 Store the observed entities in the recursion stack.
 */
 def replicatePattern = \standbyFunc. \n.
     if (n > 0) {
-        thingTemp <- waitForItem down;
+        thingTemp <- waitForItem left;
         let thing = thingTemp in
+        placeComplementOf thing;
         move;
         replicatePattern standbyFunc $ n - 1;
 
@@ -58,9 +119,11 @@ def replicatePattern = \standbyFunc. \n.
 
 def go =
     move;
-
     let sentinel = "flower" in
     place sentinel;
+
+    doN 16 $ make "cytosine";
+
     waitWhileHere sentinel;
     moveToPattern;
     replicatePattern moveToOtherRow 32;

data/scenarios/Challenges/_dna/topchecker.sw

@@ -0,0 +1,90 @@
+def doN = \n. \f. if (n > 0) {f; doN (n - 1) f} {}; end;
+
+def getBaseForNumber = \n.
+    if (n == 0) {
+        "guanine";
+    } {
+        if (n == 1) {
+            "cytosine";
+        } {
+            if (n == 2) {
+                "adenine";
+            } {
+                "thymine";
+            };
+        };
+    };
+    end;
+
+def getNumberForBase = \n.
+    if (n == "guanine") {
+        0;
+    } {
+        if (n == "cytosine") {
+            1;
+        } {
+            if (n == "adenine") {
+                2;
+            } {
+                if (n == "thymine") {
+                    3;
+                } {-1};
+            };
+        };
+    };
+    end;
+
+def getComplementNumber = \n.
+    if (n == 0) {
+        1;
+    } {
+        if (n == 1) {
+            0;
+        } {
+            if (n == 2) {
+                3;
+            } {
+                2;
+            };
+        };
+    };
+    end;
+
+def waitUntilHere = \remainingCount.
+    if (remainingCount > 0) {
+        maybeItemHere <- scan down;
+        case maybeItemHere (\_. 
+            watch down;
+            wait 1000;
+            waitUntilHere remainingCount;
+        ) (\itemHere.
+
+            maybeItemAbove <- scan left;
+            case maybeItemAbove (\_. fail "Expected an item here.") (\itemAbove.
+                let num = getNumberForBase itemAbove in
+                if (num >= 0) {
+                    let complementNum = getComplementNumber num in
+                    let complementItem = getBaseForNumber complementNum in
+                    if (complementItem == itemHere) {
+                        move;
+                        waitUntilHere $ remainingCount - 1;
+                    } {
+                        create "pixel (R)";
+                    }
+                } {
+                    fail "Expected nonnegative item index."
+                }
+            );
+        );
+    } {
+        log "Finished verifying top row";
+        create "pixel (G)";
+    };
+
+    end;
+
+def go =
+    instant $ waitUntilHere 32;
+    end;
+
+go;

data/scenarios/Challenges/_dna/verifier.sw

@@ -162,22 +162,20 @@ def spawnComplementer =
 
 def makeDnaStrand =
     teleport self (5, -2);
-    r <- spawnComplementer;
     clonedOrganism <- placeBase myStandby 32;
     doN 3 move;
     drill forward;
     teleport self (36, -12);
-    give r "gold coin";
 
     return clonedOrganism
     end;
 
 def go =
     instant $ waitUntilHere "flower";
-    // _f <- grab;
+    create "pixel (G)";
     clonedOrganism <- makeDnaStrand;
-    teleport self (40, -13);
-    place clonedOrganism;
+    // teleport self (40, -13);
+    // place clonedOrganism;
     end;
 
 go;