Josh Wardle released Wordle in October of 2021 and it soon became the hot new mobile game. Wordle has a few different gameplay modes, but the "classic" mode challenges players to guess a five-letter word. If a letter is in the correct position, it turns green. If that letter is in the word but is in the wrong position, it turns yellow. By using deductive reasoning, players must guess the correct word within six tries. But deductive reasoning is difficult, so Atomic14 modified a 3D printer to play the game for them.
A 3D printer is a robot that is very good at moving an end effector (the hot end) precisely around within a contained volume of space. That makes it great for tapping a smartphone's screen at exact points. In this case, it only needed three hardware components to solve Wordle puzzles: a stylus in place of the hot end, a camera to look at the phone's screen, and a computer to analyze what the camera sees and to deduce the words. The stylus is a generic model, the video feed comes from a Raspberry Pi Camera, and the computer is a Raspberry Pi 3 Model B. The Raspberry Pi is able to control the 3D printer through the REST interface on its Duet controller.
With this hardware, the 3D printer can solve a World puzzle in much the same way a person would. It first enters an arbitrary word. Then it checks to see if any letters match, using a computer vision script running on the Raspberry Pi. If letters do much, the Pi references a dictionary to see which words those letters could form. As it enters new words, it narrows the dictionary down until it finds the correct word. We would suggest a more efficient algorithm, based on entering three words from the start that cover the most common letters, but it is hard to argue with the results here. In most cases, the 3D printer can solve Wordle puzzles before running out of guesses.