Today, the design chain lacks adequate support, with most system-level designers using a collection of unlinked tools. The implementation then proceeds with informal techniques involving numerous human-language interactions that create unnecessary and unwanted iterations among groups of designers in different companies or different divisions. The move toward programmable platforms shifts the design implementation task toward embedded software design. When embedded software reaches the complexity typical of today's designs, the risk that the software will not function correctly increases exponentially. The Metropolis project seeks to develop a unified framework that can cope with this challenge. Based on a metamodel with formal semantics that developers can use to capture designs, Metropolis provides an environment for complex electronic-system design that supports simulation, formal analysis, and synthesis.