In this chapter, we propose a new concurrent programming approach called MACH (multi-agent extended chemical abstract machine). MACH extends the chemical abstract machine with multiple coexisting agents. This paper focuses on the design, implementation, and verification of MACH. The aim of MACH is to develop a reactive programming language based on an interactive computational model, which we believe is the key to concurrent programming. We present MACH as a simple and efficient programming approach based on a sound theoretical background.