A simple idea from the Heartland, posted on Facebook fewer than two weeks ago, is touching hearts in all 50 states, nearly 50 countries, and most continents — even Antarctica. It’s touching hearts throughout Eastern Iowa, as well. Homemade hearts are popping up in residential windows, store fronts and on sidewalks, from Dubuque to Keokuk, and all around the Corridor.Krista Wynes, 48, of Galesburg, Ill., ran across a Facebook post on March 21, showing a white house with a big red paper heart in the window, with the invitation to create a virtual scavenger hunt for hearts.Thinking this was a “really cool” idea, she decided to see if her boys, ages 8 and 11, would like to do that, then see if others would, too.