I made this a few years ago. It was my mother-in-law's idea for a craft group she was doing. She found these little white shadow box frames on sale at a craft store for 99 cents. First, we chose a Valentine themed paper as our background. We removed the back panel of the frame, traced it on the back side of the paper, cut it out, and glued the paper to the front of the back panel. Then I took the "X" and "O" which she also got from the craft store as is and glued pre-painted hearts (from the craft store) on them. I also wrapped some wire around each letter. Then the letters were glued to the paper with heavy duty glue (E6000). I also added a piece of wire and a heart to the outside bottom corner of the frame with some hot glue.
Variations: some of the other crafters painted their frame red, covered their letters with paper, and/or painted their letters.
A simple gift to put together that is great for the person that appreciates a "low calorie" Valentine.