diff --git a/CrossDown/Core.py b/CrossDown/Core.py
index 2bd158d..39cb7db 100644
--- a/CrossDown/Core.py
+++ b/CrossDown/Core.py
@@ -171,6 +171,36 @@ class Syllabus(BlockProcessor):
             return False
 
 
+class BoxBlockProcessor(BlockProcessor):
+        RE_FENCE_START = r'^ *!{3,} *\n' # start line, e.g., `   !!!! `
+        RE_FENCE_END = r'\n *!{3,}\s*$'  # last non-blank line, e.g, '!!!\n  \n\n'
+
+        def test(self, parent, block):
+            return re.match(self.RE_FENCE_START, block)
+
+        def run(self, parent, blocks):
+            original_block = blocks[0]
+            blocks[0] = re.sub(self.RE_FENCE_START, '', blocks[0])
+
+            # Find block with ending fence
+            for block_num, block in enumerate(blocks):
+                if re.search(self.RE_FENCE_END, block):
+                    # remove fence
+                    blocks[block_num] = re.sub(self.RE_FENCE_END, '', block)
+                    # render fenced area inside a new div
+                    e = etree.SubElement(parent, 'div')
+                    e.set('style', 'display: inline-block; border: 1px solid red;')
+                    self.parser.parseBlocks(e, blocks[0:block_num + 1])
+                    # remove used blocks
+                    for i in range(0, block_num + 1):
+                        blocks.pop(0)
+                    return True  # or could have had no return statement
+            # No closing marker!  Restore and do nothing
+            blocks[0] = original_block
+            return False  # equivalent to our test() routine returning False
+
+
+
 class Basic(Extension):
     """
     渲染基本样式