Start playing using the “New Game” button your iPhone. Game assumes a 4-digit number all digits being different. Objective is to find this number. You hit on every box to select a different digit, then hit “Submit” to submit your best guess. The result is in cows and bull; cows are the number of digits that are present in the assumed number but misplaced, whereas bulls are the the ones that are in the right place. You basically win when you get 4 bulls! Try it out. There is “Give up” feature for first timers to help out. Try with TestiPhone