Against the cold, gray, bleak background of Brooklyn in January, colorful things, and literally anything with the smallest hint of cheer, are sure to stand out. That’s why you may have taken a step back when confronted with the bright, cartoony, bubblegum-pink gums with pearly white teeth lining the top of buildings or plastered on walls all around Brooklyn in the past few weeks. So who is this person painting grins on all of your buildings?