Instructions
Create "Tetris" sprites using Microsoft Paint or other graphics-editing software. You can also rip "Tetris" sprites from console versions of the game using emulation software if you own the original cartridges. You will need to create seven distinct blocks at minimum for your "Tetris" game: I, J, L, O, S, T and Z.
Learn a programming language such as C++ Basic or familiarize yourself with software such as Flash if you have not already done so. If you find yourself in a hurry to learn programming, consult books such as Stephen Davis's "C++ for Dummies" and Jerry Lee Ford's "Programming for the Absolute Beginner." "How to Cheat in Adobe Flash CS5: The Art of Design and Animation" by Chris Georgenes teaches the basics of using Adobe's Flash CS5 in a fun and easy-to-understand fashion.
Use the language or software of your choice to code your "Tetris" clone. In the course of doing so, consult a web tutorial that offers information on creating your own "Tetris" clone. This allows you to get started on your game as quickly as possible without having to figure out aspects of "Tetris" programming yourself.