I think the peace sign fabric would be great for teens. Stick with modern designs, borderless, solids to complement your peace sign print. Examples like City Blocks, or the classic the shadow box design with the peace sign fabric being the 'top' square, with the shadow in black or dark gray, and a complementary solid as the background, or the square in a square pattern or the simple cobblestone pattern. The BQ pattern by Maple Island Quilts would also work well for teens, with the peace sign fabric being the large focus squares. All of these go together really quickly. Here are some photos that might give you some ideas.
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