Merge pull request #13 from mahoyen/patch-1

fixed typo, solving #12

Author: Rohit Malhotra

README.md

@@ -482,7 +482,7 @@ CONFIG = {
 ```python
 from manimlib.imports import *
 
-class ThreedSurface(ParametricSurface):
+class ThreeDSurface(ParametricSurface):
 
  def __init__(self, **kwargs):
  kwargs = {