Simple Tetris Clone in TypeScript

I wanted to create a JavaScript port of my tetris clone using the HTML5 canvas element but I never got the drive to start it, so it was lingering for ages in my TODO list. The final push come after TypeScript, a little language from the father of industrial grade languages like Delphi and C#. This was just enough to push me to use my little game to familiarize myself with this new language. 

Bitwise operators in C, JavaScript, Lua and Killa

So I thought that porting a Game Boy Advance (GBA) console emulator written in JavaScript to Killa would be fun, boy I was wrong... All because I wanted to play with this:

Dynamic programming

Dynamic Programming (DP) problems are fun, but they can be also difficult to solve. For a better definition than I could give you here I'll redirect you to the Wikipedia article, and there are some nice tutorials and sample problems in TopCoder and CodeChef. In this post I'm just going to add commentaries to the DP problem I solved previously without giving much explanation. This problem comes from the Project Euler site:

An n×n grid of squares contains n^2 ants, one ant per square.
All ants decide to move simultaneously to an adjacent square
(usually 4 possibilities, except for ants on the edge of the grid or at the corners). 
We define f(n) to be the number of ways this can happen without any ants ending on 
the same square and without any two ants crossing the same edge between two squares.
You are given that f(4) = 88. Find f(10).