We painted vertical lines in a rainbow with watercolor. We cut horizontal lines with our scissors and glued them to a black background. This was a little tricky for my students. I would have the students cut one line and then glue it on before cutting the next line. Reiterate that they need to be matching the pieces like a puzzle and make sure that the colors match up before gluing them to the black piece.
Click HERE to go to The Clever Feather to see this great idea.