# Resnick's Termite WORK IN PROGRESS { Found this in the book *The Computational Beauty of Nature*. --drummyfish } Resnick's termite is a simple [cellular automaton](cellular_automaton.md) simulating behavior of ants, demonstrating how even a very dumb behavior of a single agent can lead to higher collective intelligence once we increase the number of the agents. The simulation was made by Mitchel Resnick, the theme is similar to that of [Langton's ant](langtons_ant.md) but Resnick's termites are [stochastic](stochasticism.md), [nondeterministic](determinism.md), they rather show how statistics/[randomness](randomness.md) in behavior help many ants build tunnels in sand. The game demonstrates how randomly scattered chips start getting chunked together and form tunnels once we let ants with extremely simple behavior work together on moving the chips. Besides this demonstration however there doesn't seem to be anything more interesting going on (at least until we start to modify and tweak the thing somehow). The system is defined quite simply: we have a world made of cells, each cell can be either empty or have a wooden chip on it. In this world we have a number of ants, each of which behaves by the following [algorithm](algorithm.md): 1. Randomly walk around until you bump into a chip. 2. If you are not carrying a chip, pick up the one you bumped into, otherwise drop the chip you are carrying. Go to step 1. The original implementation had ants who had direction (up, right, down, left) and on each step could make a random turn to the right or left. If an ant bumped into a chip it turned 180 degrees. 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'-' : ' '); putchar('\n'); } void printWorld(void) { printHBorder(); for (int y = 0; y < WORLD_SIZE; y += 2) { putchar('|'); for (int x = 0; x < WORLD_SIZE; ++x) { int n = y * WORLD_SIZE + x; switch ((world[n] << 1) | (world[n + WORLD_SIZE])) { case 1: putchar('\''); break; case 2: putchar(','); break; case 3: putchar(';'); break; default: putchar(' '); break; } } putchar('|'); putchar('\n'); } printHBorder(); } void updateAnts(void) { for (int i = 0; i < ANTS; ++i) { int newPos = // this just randomly moves in one direction (WORLD_SIZE * WORLD_SIZE + ants[i].pos + ((rand() % 2) ? ((rand() % 2) ? -1 : 1) : ((rand() % 2) ? -1 * WORLD_SIZE : WORLD_SIZE))) % (WORLD_SIZE * WORLD_SIZE); if (world[newPos]) // stepped on a chip? { if (ants[i].chip) { // has chip; drop the chip if (!world[ants[i].pos]) { ants[i].chip = 0; world[ants[i].pos] = 1; } } else { // no chip; pick up the chip world[newPos] = 0; ants[i].chip = 1; } } ants[i].pos = newPos; } } int main(void) { srand(123); for (int i = 0; i < WORLD_SIZE * WORLD_SIZE; ++i) world[i] = (rand() % CHIP_DENSITY) == 0; for (int i = 0; i < ANTS; ++i) { ants[i].pos = rand() % (WORLD_SIZE * WORLD_SIZE); ants[i].chip = 0; } int i; while (1) { if (i % 65536 == 0) { printf("iteration %d:\n",i); printWorld(); } updateAnts(); i++; } printWorld(); return 0; } ```