diff --git a/converters/reveal.py b/converters/reveal.py
index 6654459..2cbc5f7 100644
--- a/converters/reveal.py
+++ b/converters/reveal.py
@@ -5,7 +5,12 @@ import os
 class ConverterReveal(ConverterMarkdown):
     """Convert a notebook to a html slideshow.
 
-    It generates a static html slideshow based in markdown and reveal.js. 
+    It generates a static html slideshow based in markdown and reveal.js.
+    You have four ways to delimit the the slides: 
+    ##--- delimit horizontal slides
+    ##<<< open vertical slides
+    ##>>> close vertical slides
+    ##>>><<< close vertical slides and open new vertical slides. 
     """
 
     def __init__(self, infile, highlight_source=False, show_prompts=True,
@@ -34,12 +39,18 @@ class ConverterReveal(ConverterMarkdown):
         """
         lines = []
         lines.extend(self.optional_header())
-        top = '<section data-markdown><script type="text/template">'
-        bottom = '</script></section>'
+        left = '<section data-markdown><script type="text/template">'
+        right = '</script></section>'
         text = self.main_body(cell_separator)
         for i,j in enumerate(text):
-            if j == u'---':
-                text[i] = bottom + top 
+            if j == u'##---':
+                text[i] = right + left
+            if j == u'##<<<':
+                text[i] = right + '<section>' + left
+            if j == u'##>>>':
+                text[i] = right + '</section>' + left
+            if j == u'##>>><<<':
+                text[i] = right + '</section><section>' + left
         lines.extend(text)
         lines.extend(self.optional_footer())
         return u'\n'.join(lines)
diff --git a/example_slide.ipynb b/example_slide.ipynb
index 1965635..b705225 100644
--- a/example_slide.ipynb
+++ b/example_slide.ipynb
@@ -1,6 +1,6 @@
 {
  "metadata": {
-  "name": "test_example_slide"
+  "name": "example_slide"
  },
  "nbformat": 3,
  "nbformat_minor": 0,
@@ -33,7 +33,7 @@
      "cell_type": "markdown",
      "metadata": {},
      "source": [
-      "---"
+      "##<<<"
      ]
     },
     {
@@ -55,7 +55,7 @@
      "cell_type": "markdown",
      "metadata": {},
      "source": [
-      "---"
+      "##---"
      ]
     },
     {
@@ -69,7 +69,7 @@
      "cell_type": "markdown",
      "metadata": {},
      "source": [
-      "---"
+      "##---"
      ]
     },
     {
@@ -85,7 +85,7 @@
      "cell_type": "markdown",
      "metadata": {},
      "source": [
-      "---"
+      "##>>><<<"
      ]
     },
     {
@@ -111,7 +111,7 @@
      "cell_type": "markdown",
      "metadata": {},
      "source": [
-      "---"
+      "##---"
      ]
     },
     {
@@ -125,7 +125,7 @@
      "cell_type": "markdown",
      "metadata": {},
      "source": [
-      "---"
+      "##---"
      ]
     },
     {
@@ -150,7 +150,7 @@
      "cell_type": "markdown",
      "metadata": {},
      "source": [
-      "---"
+      "##>>><<<"
      ]
     },
     {
@@ -172,7 +172,7 @@
      "cell_type": "markdown",
      "metadata": {},
      "source": [
-      "---"
+      "##---"
      ]
     },
     {
@@ -189,7 +189,7 @@
      "cell_type": "markdown",
      "metadata": {},
      "source": [
-      "---"
+      "##---"
      ]
     },
     {
@@ -205,7 +205,7 @@
      "cell_type": "markdown",
      "metadata": {},
      "source": [
-      "---"
+      "##---"
      ]
     },
     {
@@ -221,7 +221,7 @@
      "cell_type": "markdown",
      "metadata": {},
      "source": [
-      "---"
+      "##>>>"
      ]
     },
     {
@@ -245,7 +245,7 @@
      "cell_type": "markdown",
      "metadata": {},
      "source": [
-      "---"
+      "##---"
      ]
     },
     {
@@ -289,7 +289,7 @@
      "cell_type": "markdown",
      "metadata": {},
      "source": [
-      "---"
+      "##---"
      ]
     },
     {
@@ -330,7 +330,7 @@
      "cell_type": "markdown",
      "metadata": {},
      "source": [
-      "---"
+      "##---"
      ]
     },
     {
@@ -350,7 +350,7 @@
      "cell_type": "markdown",
      "metadata": {},
      "source": [
-      "---"
+      "##<<<"
      ]
     },
     {
@@ -381,7 +381,7 @@
      "cell_type": "markdown",
      "metadata": {},
      "source": [
-      "---"
+      "##---"
      ]
     },
     {
@@ -407,7 +407,7 @@
      "cell_type": "markdown",
      "metadata": {},
      "source": [
-      "---"
+      "##>>>"
      ]
     },
     {
@@ -428,7 +428,7 @@
      "cell_type": "markdown",
      "metadata": {},
      "source": [
-      "---"
+      "##---"
      ]
     },
     {