At the front of the band is a cockade of blue and yellow, the colours of the Swedish flag. Swedish student caps traditionally come in two main variants, named after the two universities in existence at the time of their original adoption. The "Uppsala cap" has a black band, blue and yellow lining, and a somewhat soft crown. The "Lund cap" has a dark blue band, red lining, and a stiffer crown. The earliest student cap known to have been preserved, a mid-19th century Uppsala cap in the collections of the Nordic Museum but currently exhibited at the Uppland Provincial Museum (in Uppsala), is considerably softer and looser in style than the modern or even late 19th century caps. The Uppsala cap was traditionally worn only in summer, from Walpurgis Night until the end of September. In Lund, the white cap was also donned at Walpurgis and taken off in the fall, but students could exchange it for a winter variant with a dark blue crown during the rest of the year. Nowadays, the cap is usually only worn during the single annual event of Walpurgis Night, and no winter variant exists anymore. A major variation on the student cap is the one worn by engineering students, the "teknologmössa", which has the same basic shape as the regular student cap but has a triangular flap hanging down on the right side ending in a tassel. The caps worn by engineering students usually come in colours signalling the university of origin (e.g. white=Chalmers University of Technology in Gothenburg, wine red=Luleå University of Technology). The tasseled cap originated at the Chalmers University of Technology in Gothenburg, where it was first introduced in 1879, and is influenced by the Norwegian student cap, the "duskelue", which from 1856 had a tassel; during the period of the Swedish-Norwegian union (until 1905) a large number of Norwegian students studied at Chalmers. It later spread to the Royal Institute of Technology and the other Swedish engineering schools. Originally associated with completion of the "studentexamen", the entrance examination to the universities, which was at the time of the original adoption of student caps always taken at the universities, the cap followed the "studentexamen" to the secondary schools when these took over the final examination of their students in 1864. After this point it was donned upon graduation by everyone who completed the "studentexamen", whether they continued to university or not.