diff --git a/playground/playground.js b/playground/playground.js
index 800894bb9..47631b201 100644
--- a/playground/playground.js
+++ b/playground/playground.js
@@ -78,6 +78,9 @@ window.onload = function() {
     vm.on('BLOCK_GLOW_OFF', function(data) {
         workspace.glowBlock(data.id, false);
     });
+    vm.on('VISUAL_REPORT', function(data) {
+        workspace.reportValue(data.id, data.value);
+    });
 
     // Run threads
     vm.start();
diff --git a/src/engine/execute.js b/src/engine/execute.js
index 529990ca0..db111637d 100644
--- a/src/engine/execute.js
+++ b/src/engine/execute.js
@@ -96,6 +96,10 @@ var execute = function (sequencer, thread) {
         primitiveReportedValue.then(function(resolvedValue) {
             // Promise resolved: the primitive reported a value.
             thread.pushReportedValue(resolvedValue);
+            // Report the value visually if necessary.
+            if (thread.peekStack() === thread.topBlock) {
+                runtime.visualReport(thread.peekStack(), resolvedValue);
+            }
             thread.setStatus(Thread.STATUS_RUNNING);
             sequencer.proceedThread(thread);
         }, function(rejectionReason) {
@@ -107,6 +111,10 @@ var execute = function (sequencer, thread) {
         });
     } else if (thread.status === Thread.STATUS_RUNNING) {
         thread.pushReportedValue(primitiveReportedValue);
+        // Report the value visually if necessary.
+        if (thread.peekStack() === thread.topBlock) {
+            runtime.visualReport(thread.peekStack(), primitiveReportedValue);
+        }
     }
 };
 
diff --git a/src/engine/runtime.js b/src/engine/runtime.js
index c51be795d..f92a91db7 100644
--- a/src/engine/runtime.js
+++ b/src/engine/runtime.js
@@ -69,6 +69,12 @@ Runtime.BLOCK_GLOW_ON = 'BLOCK_GLOW_ON';
  */
 Runtime.BLOCK_GLOW_OFF = 'BLOCK_GLOW_OFF';
 
+/**
+ * Event name for visual value report.
+ * @const {string}
+ */
+Runtime.VISUAL_REPORT = 'VISUAL_REPORT';
+
 /**
  * Inherit from EventEmitter
  */
@@ -218,6 +224,15 @@ Runtime.prototype.glowBlock = function (blockId, isGlowing) {
     }
 };
 
+/**
+ * Emit value for reporter to show in the blocks.
+ * @param {string} blockId ID for the block.
+ * @param {string} value Value to show associated with the block.
+ */
+Runtime.prototype.visualReport = function (blockId, value) {
+    this.emit(Runtime.VISUAL_REPORT, blockId, String(value));
+};
+
 /**
  * Return the Target for a particular thread.
  * @param {!Thread} thread Thread to determine target for.
diff --git a/src/index.js b/src/index.js
index 15b218071..965c8cd9a 100644
--- a/src/index.js
+++ b/src/index.js
@@ -53,6 +53,9 @@ function VirtualMachine () {
     instance.runtime.on(Runtime.BLOCK_GLOW_OFF, function (id) {
         instance.emit(Runtime.BLOCK_GLOW_OFF, {id: id});
     });
+    instance.runtime.on(Runtime.VISUAL_REPORT, function (id, value) {
+        instance.emit(Runtime.VISUAL_REPORT, {id: id, value: value});
+    });
 }
 
 /**
@@ -158,6 +161,9 @@ if (ENV_WORKER) {
     self.vmInstance.runtime.on(Runtime.BLOCK_GLOW_OFF, function (id) {
         self.postMessage({method: Runtime.BLOCK_GLOW_OFF, id: id});
     });
+    self.vmInstance.runtime.on(Runtime.VISUAL_REPORT, function (id, value) {
+        self.postMessage({method: Runtime.VISUAL_REPORT, id: id, value: value});
+    });
 }
 
 /**