Fraske Design's got a great, simple tutorial for making your own Tetris brownies for hours of fun and pounds of flab:
Since I made these brownies thinner than normal, I also cut down the baking time. The baking process would have normally taken around 30 minutes, but this batch only took 10. I just kept an eye on the pan and took it out when it looked about right. The trick is to not let them bake too long.
Next, while the brownies were cooling, I mixed up my tetris color frostings into seven separate bowls. It turns out that Tetris colors have varied over the years, so I settled on matching the colors to the tetrads in the Free Tetris game online. My colors included yellow, orange, red, magenta, cyan, blue, and green. I achieved these colors mixing white vanilla frosting and food coloring accordingly.