GRAND RAPIDS, Mich. — All around me, swarms of people with faces caught between eagerness and beleaguerment are gravitating towards a giant paper blow-up of a detail of the American flag. It spans at least six feet and culminates in a portrait of a dirty-blonde-haired, blue-eyed, red-faced soldier. Titled “Hometown Hero,” the piece is a memorial to a young local soldier who died at war, as well as an entry in ArtPrize (it made the public’s top 20 list). The work’s explanatory text bills it as “touchable art” and invites viewers to add a “name, date, or tiny doodles to the stars and stripes … to commemorate the life of their hero.” People do so with such zeal — the stars and stripes so densely coated with names and doodles — that “Hometown Hero” seems just one step away from a graffiti-covered alley wall in Detroit. The main difference, perhaps, is the writing utensils. In this case they are black Sharpies, each with a small American flag attached to the end.