Sir George Sitwell gave a lucid, instructive and occasionally amusing explanation of this development. His lectures were interesting, instructive, and suggestive. This very simple model is quite instructive. Some helpful and instructive basic properties can be obtained immediately. The game was advertised as "entertaining, instructive and solidly constructed". The book was advertised in June 1729 as being "very entertaining and instructive for children". The first reading implies that all literature must be instructive. He is kind and instructive but also very stern. However, there is another method which is as accurate and is usually more instructive. Karney discusses Greenland as an instructive example. Luttwak states that there are "instructive similarities" between Roman and modern military strategy. Briers argues that the denial of the existence of failure diminishes its instructive value. Viral videos continue to increase in popularity as teaching and instructive aids. De Young purchased many things of "curious and artistic and instructive value" for the museum. See an instructive example for C# language below.