diff --git a/core/src/processing/core/PShape.java b/core/src/processing/core/PShape.java
index 8420f72f6..d0db5006b 100644
--- a/core/src/processing/core/PShape.java
+++ b/core/src/processing/core/PShape.java
@@ -2065,7 +2065,12 @@ public class PShape implements PConstants {
 
     vertices[index][X] = vec.x;
     vertices[index][Y] = vec.y;
-    vertices[index][Z] = vec.z;
+
+    if (vertices[index].length > 2) {
+      vertices[index][Z] = vec.z;
+    } else if (vec.z != 0 && vec.z == vec.z) {
+      throw new IllegalArgumentException("Cannot set a z-coordinate on a 2D shape");
+    }
   }
 
 
diff --git a/core/todo.txt b/core/todo.txt
index 3ee3c95b7..99af134bb 100644
--- a/core/todo.txt
+++ b/core/todo.txt
@@ -4,6 +4,8 @@ X   https://github.com/processing/processing/issues/2228
 X   https://github.com/processing/processing/pull/2324
 X move to native OS X full screen (gets rid of native code)
 X   https://github.com/processing/processing/issues/2641
+X do bounds check on setVertex(PVector)
+X   https://github.com/processing/processing/issues/2556
 
 data
 X add copy() method to Table