VB 1.0 was introduced in 1991. The drag and drop design for creating the user interface is derived from a prototype form generator developed by Alan Cooper and his company called "Tripod". Microsoft contracted with Cooper and his associates to develop Tripod into a programmable form system for Windows 3.0, under the code name "Ruby" (no relation to the Ruby programming language). Tripod did not include a programming language at all. Microsoft decided to combine Ruby with the Basic language to create Visual Basic. The Ruby interface generator provided the "visual" part of Visual Basic and this was combined with the "EB" Embedded BASIC engine designed for Microsoft's abandoned "Omega" database system. Ruby also provided the ability to load dynamic link libraries containing additional controls (then called "gizmos"), which later became the Visual Basic Extension (VBX) interface. Versions of Visual Basic are listed below: