Origami is the traditional Japanese art of paper folding that originated in the 17th century in Japan and was later popularized worldwide in the mid-1900s. It has since evolved into a modern art form. While origami's exact origins are unknown due to lack of evidence, it has a long history in Japan as well as independent traditions that developed in other countries like China, Germany, Italy and Spain. Tools like bone folders and tweezers can help with complex folds, but origami can also be done using just the hands. Origami art includes both static designs as well as ones that incorporate movement. Computer programs now also exist to aid in the design and analysis of origami creations.