Kenneth Iverson developed a programming language known as Iverson Notation, the programming language was used for manipulating arrays that he taught his students. IBM hired Iverson and together with Adam Falkoff they created APL based on the notation he had developed. Its central datatype is the multidimensional array. It uses a large range of special graphic symbols to represent most functions and operators, leading to very concise code. APL has been an important influence concept modeling, spreadsheets, functional programming and computer math packages. It has inspired several other programming languages and it still used for some applications today.