Algorithmic worlds

About algorithmic worlds

Invaders

This pattern was inspired by a work at complexification.net.

"Invaders" refers to Space Invaders, one of the first informatic games, released in 1978. This game consisted in shooting from a spacecraft on extraterrestrial "invaders". Because of the poor resolution of the computer screens at this time, the latter were coarsely represented by two-color 10x10 pixel matrices.

The "Invaders" pattern divides the plane into squares, and further divides these squares into pixels. It attributes randomly to each of these pixel an index value among two possible ones. Interestingly, if one forces a vertical mirror symmetry on each of these pixel matrices, and provided the number of pixels is not too big, patterns reminiscent of Space Invaders appear. For instance, the image below depicts 5x5 pixel invaders.

Here are 7x7 pixel invaders (note the three-eyed octopus in the third row, second column).

Of course, it is not necessary to impose a vertical symmetry. The following invaders have an order four rotational symmetry.

Finally here are 20x20 pixel invaders with an order four dihedral symmetry (the symmetry group of the square, with vertical, horizontal and diagonal mirrors).

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