The small number of basic origami folds can be combined in a variety of ways to make intricate designs. The best-known origami model is the Japanese paper crane. In general, these designs begin with a square sheet of paper whose sides may be of different colors, prints, or patterns.
On 30 June 2017 the city-state of Berlin had a population of 3.69 million registered inhabitants in an area of 891.85 km 2 (344.35 sq mi). The city's population density was 4,048 inhabitants per km 2. Berlin is the second most populous city proper in the EU.
It is particularly large in the city states of Berlin (-176,000 people or -5.0%) and Hamburg (81,000 people or -4.5%). Thus not more than 3.3 million people lived in Berlin on 31 December 2011, while the number of inÂ­habiÂ­tants of Hamburg was 1.7 million.