diff --git a/core/block.js b/core/block.js
index 955b01c72d..c799d023f5 100644
--- a/core/block.js
+++ b/core/block.js
@@ -1499,6 +1499,9 @@ Blockly.Block.prototype.interpolate_ = function(message, args, lastDummyAlign) {
       if (field) {
         fieldStack.push([field, element['name']]);
       } else if (input) {
+        if (element['shape']) {
+          input.setShape(element['shape']);
+        }
         if (element['check']) {
           input.setCheck(element['check']);
         }
diff --git a/core/input.js b/core/input.js
index 91bb4f12bf..6c23e30d86 100644
--- a/core/input.js
+++ b/core/input.js
@@ -218,6 +218,14 @@ Blockly.Input.prototype.setCheck = function(check) {
   return this;
 };
 
+Blockly.Input.prototype.setShape = function(shape) {
+  if (!this.connection) {
+    throw 'This input does not have a connection.';
+  }
+  this.connection.setShape(shape);
+  return this;
+};
+
 /**
  * Change the alignment of the connection's field(s).
  * @param {number} align One of Blockly.ALIGN_LEFT, ALIGN_CENTRE, ALIGN_RIGHT.