A tribute to photographer Josef Koudelka (Invasion 68) made in visual arts programming language Processing. I coded a variant of Game of Life (GOL) called Game of Pixel (GOP). GOP works as follows. I start with a bitmap image and represent each image pixel as a cell of the GOL. As for the initial configuration of the game, I adopted the following rule: If the relative luminance of a pixel is larger than a noisy value around 0.5, then the pixel cell is alive, otherwise it is dead. I computed relative luminance (L) as usual: L = 0.2126 * R + 0.7152 * G + 0.0722 * B, where R, G and B are the red, green, and blue components (scaled [0,1]) of the pixel’s color, respectively. Given this initial configuration, I let the game run on a selected image and applied the following rule at each generation of the game: If a pixel is alive it is pictured with its complementary color, otherwise with its original color. The effect is as if images are invaded by a colony of artificial life that feeds of pixels, expanding along unpredictable paths, apparently never-ending. In fact, since any image has a finite number of pixels, the possible configuration states of the game are also finite, and hence eventually the game repeats itself. However, when this will happen is not easy to predict in advance. I ran GOP on an iconic photography shot by Josef Koudelka during the 1968 Prague invasion. Read more at https://medium.com/@hex6c/game-of-pixel-46dda248f938