Bulls and Cows

Classical number guessing game "Bulls and Cows" (also known as Mastermind).

Computer picked up 4 different digits - your goal is to guess them.  Your guess has to consist of the same number of digits, also different. For each of your guesses computer replies with a number of "Cows" and "Bulls", where

• "Cows" means the number of correct digits but in the wrong position
• "Bulls" means the number of correct digits in the correct position

Try to guess computer's digits in the fewest moves possible and post your results in the comments:)

The game was made entirely in Elm programming language. The chances are you've never heard of it, but I promise it's quite interesting and unusual. It was my first game made in Elm and I'll make a video about it on my YouTube channel. While the video is not up yet, you might find interesting how I made a nice maze game in just 8.5 minutes: