Mastermind: the four colours that beat me
The board read Exact: 0, Colour: 4, and I froze. All four colours guessed, none in its place. Ten tries for a 4-colour code, and on the sixth move I realised I was shuffling options blind.
The Clue I Failed to Read
The game started briskly. My first guess gave Exact: 1, Colour: 1: one colour sat where it should, one more was present but elsewhere. I filled the slots with the colour buttons, pressed Check, and wrote the hints on scrap paper. By the fourth move the paper held everything needed. My head held porridge.
The mistake sat right there: I swapped two or three slots at a time. A hint after such a move says nothing about any single colour. Exact: 2 after a double swap is a riddle with two unknowns. A proper interrogation takes one suspect at a time: change one slot, watch how the numbers shift.
How the Machine Interrogates
In demo mode the AI cracks the code itself by cutting out every option the hints rule out. No gut feeling, no maybes. I replayed such a game and spotted the trick: the machine holds one slot as an anchor until its colour is settled for good.
I tried the same in my next game. I pinned the first slot and shuffled the rest. By the seventh try the board read Exact: 3. The code fell on the eighth. Ten tries is a generous limit if you stop spending them on guessing.
What Stayed on the Paper
Click a filled slot to clear it — a trifle that speeds the interrogation. The New game button deals a fresh code, and I press it more often than I would like to admit. My paper from that lost game still lies by the keyboard: E0 C4. A reminder that I held every clue four moves before the defeat.