These copper prisms were exactly what I was looking for to accent a bare wall in our dining room. I hung all 6 of them yesterday evening with the clear pieces and 3M strips provided. I woke up this morning and EVERY SINGLE prism had fallen off, leaving behind only the 3M strips on the wall. So disappointing (and a sticky mess). I suppose I will have to hang these with nails. If you haven't hung yours yet - use nails!