The Alan Turing Google Doodle is an interactive programming puzzle released on June 23, 2012, celebrating what would have been the 100th birthday of the father of computer science. It’s one of Google’s geekiest Doodles ever — a working simulation of a Turing Machine that challenges you to think in binary and solve logic puzzles just like the man who helped crack Nazi codes and invented the theoretical foundation for every computer we use today.
Alan Turing was a British mathematician born in 1912 who changed the world in ways most people never realised. In 1936, he invented the concept of the Turing Machine — a theoretical device that manipulates symbols on a strip of tape according to a table of rules. This abstract idea formalized what it means to compute a number and became the blueprint for modern computers. During World War II, he worked at Bletchley Park where his team cracked the German Enigma cipher, allowing the Allies to intercept enemy messages. Historians believe this shortened the war by years and saved countless lives. He also pioneered artificial intelligence and created the famous Turing Test to determine if a machine can think.
Google’s Doodle recreates a simplified Turing Machine with twelve interactive puzzles. When you first load it, the machine runs a binary counter program, cycling through numbers in 1s and 0s. Click the green play button and you’re presented with programming challenges. Your goal is to make the binary number on the tape match the target number shown in the box — and with each puzzle you solve, another letter of the Google logo fills with colour.
The Doodle uses a visual programming language with symbols along the bottom. Arrows move the tape left or right. Numbers tell the machine to write that value. Squares trigger conditional logic based on what the tape currently shows. It’s surprisingly deep — after completing the first six “easy” puzzles, you unlock six harder ones. And if you finish everything, a hidden bunny icon appears that runs a complex program calculating the Fibonacci-like “rabbit sequence.”
How To Play Alan Turing Google Doodle
Click the green play button to start the puzzle mode. The machine will present a target binary number in the top-right corner.
Your goal is to program the machine so the tape displays the target number. Click the yellow/orange buttons to change the instructions — cycling through arrows, numbers (0, 1), and blank.
Press play to run your program. Watch the machine execute your instructions from left to right. If the tape matches the target, the puzzle is solved and a letter of Google lights up.
Complete all six puzzles to unlock six harder challenges. After finishing everything, look for the bunny icon to discover a secret bonus program.
The key is understanding binary: computers count using only 0 and 1, so the sequence goes 0, 1, 10, 11, 100, 101, 110, 111, and so on.