The classic game of logic, Bulls & Cows; this time, with four-letter words. The computer plays a pretty good game but can be beaten with a little effort! (In fact, the computer is at a distinct disadvantage as it avoids words that are not well established, rarely used or obscene.)
To make a guess, type in a four-letter word. To give a clue, type in the number of bulls (black marks) and cows (white marks). Use backspace and the arrow keys to make adjustments and hit enter when done.