For Sharon Hart, the third day after her chemotherapy treatment for her leukemia is always the hardest. But this time, her 14-year-old son told her to look out the window of her Chicago hospital room. His giant message in the newly fallen snow made some of the pain go away.

On top of a 6-story parking garage, her son William stomped out HI MOM with a smiley face inside the "o".

The message brought cheer to the entire staff of Rush Medical Center and all the patients with a window view.

(WATCH the video below, or READ the story in the Chicago Tribune)