diff --git a/README.md b/README.md
index 89c4025..b7a787f 100644
--- a/README.md
+++ b/README.md
@@ -22,6 +22,15 @@ Some are in Jupyter (IPython) notebooks, some in `.py` files. You can view the f
|[When Cheryl Met Eve: A Birthday Story](https://github.com/norvig/pytudes/blob/master/ipynb/Cheryl-and-Eve.ipynb)
*Inventing new puzzles in the Style of Cheryl's Birthday.*|
|[Sol Golomb's Rectangle Puzzle](https://github.com/norvig/pytudes/blob/master/ipynb/Golomb-Puzzle.ipynb)
*A Puzzle involving placing rectangles of different sizes inside a square. Bonus: cryptarithmetic.*|
|[WWW: Will Warriors Win?](https://github.com/norvig/pytudes/blob/master/ipynb/WWW.ipynb)
*Golden State Warriors probability of winning the 2016 NBA title.*|
+|[The Riddler: Battle Royale](https://github.com/norvig/pytudes/blob/master/ipynb/Riddler%20Battle%20Royale.ipynb)
*A puzzle involving allocating your troops and going up against an opponent.*|
+
+|More Serious Math Stuff|
+|---|
+|[A Concrete Introduction to Probability](https://github.com/norvig/pytudes/blob/master/ipynb/Probability.ipynb)
*Code and examples of the basic principles of Probability Theory.*|
+|[Probability, Paradox, and the Reasonable Person Principle](https://github.com/norvig/pytudes/blob/master/ipynb/ProbabilityParadox.ipynb)
*Some classic paradoxes in Probability Theory, and how to think about disagreements.*|
+|[Symbolic Algebra, Simplification, and Differentiation](https://github.com/norvig/pytudes/blob/master/ipynb/Differentiation.ipynb)
*A computer algebra system to manipulate expressions. including symbolic differentiation.*|
+|[Economics Simulation](https://github.com/norvig/pytudes/blob/master/ipynb/Economics.ipynb)
*A simulation of a simple economic game.*|
+|[How to Count Things](https://github.com/norvig/pytudes/blob/master/ipynb/How%20To%20Count%20Things.ipynb)
*Combinatorial math: how to count how many things there are, when there are a lot of them.*|
|Word Games|
|---|
@@ -36,15 +45,12 @@ Some are in Jupyter (IPython) notebooks, some in `.py` files. You can view the f
|Computer Science Algorithms, Concepts, and Problems|
|---|
-|[A Chaos Game with Triangles](https://github.com/norvig/pytudes/blob/master/ipynb/Sierpinski.ipynb)
*A surprising appearance of the Sierpinski triangle in a random walk between vertexes.*|
|[BASIC Interpreter](https://github.com/norvig/pytudes/blob/master/ipynb/BASIC.ipynb)
*How to write an interpreter for the BASIC programming language.*|
|[Bad Grade, Good Experience](https://github.com/norvig/pytudes/blob/master/ipynb/Snobol.ipynb)
*As a student, did you ever get a bad grade on a programming assignment? (Snobol, Concordance)*|
|[Conway's Game of Life](https://github.com/norvig/pytudes/blob/master/ipynb/Life.ipynb)
*The cellular automata zero-player game.*|
-|[A Concrete Introduction to Probability](https://github.com/norvig/pytudes/blob/master/ipynb/Probability.ipynb)
*Code and examples of the basic principles of Probability Theory.*|
-|[Probability, Paradox, and the Reasonable Person Principle](https://github.com/norvig/pytudes/blob/master/ipynb/ProbabilityParadox.ipynb)
*Some classic paradoxes in Probability Theory, and how to think about disagreements.*|
+|[A Chaos Game with Triangles](https://github.com/norvig/pytudes/blob/master/ipynb/Sierpinski.ipynb)
*A surprising appearance of the Sierpinski triangle in a random walk between vertexes.*|
|[The Convex Hull Problem](https://github.com/norvig/pytudes/blob/master/ipynb/Convex%20Hull.ipynb)
*A classic Computer Science Algorithm.*|
|[The Traveling Salesperson Problem](https://github.com/norvig/pytudes/blob/master/ipynb/TSP.ipynb)
*Another of the classics.*|
-|[Economics Simulation](https://github.com/norvig/pytudes/blob/master/ipynb/Economics.ipynb)
*A simulation of a simple economic game.*|
|[Project Euler Utilities](https://github.com/norvig/pytudes/blob/master/ipynb/Project%20Euler%20Utils.ipynb)
*My utility functions for the Project Euler problems, including `Primes` and `Factors`.*|
# Index of Python Files