What is Celtic art?

Celtic art is ornamental, avoiding straight lines and only occasionally using symmetry, without the imitation of nature or ideal of beauty central to the classical tradition, but as far as we can understand it often involves complex symbolism. It includes a variety of styles and often incorporates subtly modified elements from other cultures, an example being the characteristic over-and-under interlacing-weaving-which only arrived in the 6th century when it was already in extensive use by neighboring Germanic people. There are three "traditions" of Celtic art, the first being the continental Iron age art mainly associated with La Tène culture which draws on native, classical and (perhaps via the Mediterranean) oriental sources. The second, Iron Age art in Britain and Ireland, draws on the continental tradition while adding distinctive regional styles. The third, the Celtic "renaissance" of the early Middle Ages in Ireland and parts of Britain, is also called Insular art. This third tradition formed the basis for art of the Celtic revival beginning in the late 19th century. It is extremely beautiful in writing, pictures or sculptures. Can i get the short version please?