Brian Mueller can make anything hilarious. Even the weather.Brian Mueller is something of a Renaissance man. He single-handedly codes, designs, illustrates, and writes all of the dialogue for his wisecracking Carrot apps, which fall into categories that typically don’t have a lot of personality: to-do lists, alarm clocks, calorie counters. To call his style droll would be an understatement. The exercise app Carrot Fit, for instance, implores you to “jump flabby human, jump for freedom!” in a dea...