In the computer game Tetris there are six differently shaped blocks or tetrominoes. Each block consists of four square, connected by an entire edge.
These blocks, being of different shapes, end up being fitted into the tetris pit in a variety of different ways. Because of this, some may end up being considered more cool than others.

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The I-shaped Tetris Block
This block is known for being incredibly useful. If you have a vertical hole anywhere, you can just shove this into it and watch as the long, smooth shaft of the block slides perfectly into the crevice. Sometimes I build up a solid mass everywhere except one vertical mine-shaft down into the pit, waiting for one of these marvellous guys to come around and jump into it. However, the ease with which this can be fitted into the Tetris pit causes many to consider it a loser block - one that any newbie can perfect the use of with the greatest of ease, a block that requires no intellectual effort, no concentration, no strategy..

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The L-shaped Tetris Block
Like the I-shaped block, this block has a long end to it, perfect for filling up vertical holes in the mass of blocks. However, the hook on the end will catch the edge of thin passages, making it more difficult to correctly utilise than the simplistic I block. I consider it quite lovely in form and function.

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The Gamma-shaped Tetris Block
A reflected image of the L-block, this too has a long and a hook. It can make some nice and pretty shapes, if you want.

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The S-shaped Tetris Block
A beautiful piece of work, this block is. Perfect for filling up little hole or one-square size, as long as there is ample space for it on the pit level above said hole. It can also fill up two-square gaps, also provided there is space above for him to rest his weary head. An unhelpful strategy which can be performed easily with these blocks is stacking them on top of each other to form a big tower.

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The Z-shaped Tetris Block
Little more than a mirror image of the S Block, this block fits into the same type of holes, merely the other way around. When building a tower, the two are best not used together, as they do not fit into each other.

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The Square Tetris Block
A totally uncooperative lump of tetris matter. This has no funky tendrils, protrusions, lumps, cancer, or other things sticking out of it anywhere. It just sits there, doing nothing to help you play the game in any way. When placed on top of another block it usually leaves a hole underneath it. A royal pain in the ass. Avoid it if at all possible.

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The Tetris Block in the Shape of the Arrow Keys on my Keyboard
A total masterpiece. This is a Rembrandt, a Beethoven, a Savage Garden, a Blizzard. This is a divinely inspired piece of work. This is one block you don't want to miss.
Able to fit into all kinds of nooks and crannies in amazing, creative and exciting ways, this single block can be the key to winning or losing a game. Never waste one - every time you are given one by the unknowable mind determining the blocks handed out, you must use it wisely. Practise with these, until you are certain you know every little thing there is to know about them - their structure, their behaviour, their applications, their lifestyles, their tastes in clothing, etc.
Whenever I find one of these, I get a surge of adrenaline and rush of other hormones, and sometimes have to pause the game and wait for it to die down so that I can actually concentrate on what I want to do with this fantastic block.

You may reach different conclusions, but if you disagree with me then you are wrong.