perfect snowboy in Animal Crossing: New Horizons every time.

What is a perfect snowboy in ‘Animal Crossing: New Horizons’?
From Dec. 11 to Feb. 24, you can find two snowballs on your island every day to build a snowboy. But nobody’s perfect, so why does the snowboy have to be? Technically, you can roll the snowballs to whatever sizes you’d like without penalty, but getting them just right comes with gifts.