Tetris 4G
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About
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“Tetris 4G“ is a 2D online casual game, inspired by “Tetris”.

Game rules / description
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The playing field consists of about a 30 x 30 grid (variable). In the middle of the field, new geometry objects (Tetris-like) spawn. The player´s task is to move them to a wall, where he has to build full lines that disappear. What distinguishes “Tetris 4G” from Tetris is the “4G”: while Tetris uses one ground and a sky, Tetris 4G has gravity at all four borders of the playing field. The nearer objects are to the center point, the greater gets the gravity to a certain direction. If an object is located in the middle and a new object spawns on top of it, the game is lost.

Technical description
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Gravity is defined by “gravity lines”: at each wall, the block located the furthest from the wall makes up the gravity line on it´s height, parallel to the wall.
Forces on objects are calculated by addition of all four gravities and so is the velocity. Forces are calculated by the distances to the gravity lines
The player can influence the movement of an object by hitting the arrow keys. This adds forces to the calculation.
The game contains missions: e.g. “build 2 lines at wall 4 in 25 sec.”. Rewards for missions are items such as increasing the power of the arrow keys for a period of time.

Programming
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HTML 5, CSS
Javascript (ECMAScript)
jQuery (http://jquery.com/)
Processing.js (http://processingjs.org/)

License
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“Tetris 4G” is licensed under the GNU GENERAL PUBLIC LICENSE http://www.gnu.org/licenses/gpl.txt

Copyright © 2010 by Anton Pirogov and Felix Wiemuth