System Landscape/Application Landscape

In the above diagram, you can see three scenarios. In the first scenario, there are three different servers for three environments (Dev, Test and Production).
In the second scenario, both development and Test systems are placed in one server. Production is different server.
In the third scenario, we will find SAND BOX, Let me explain what SAND BOX is, it is also a server that you can use for development activities. In the system landscape SAND BOX is placed before Development system/server. I.e. SAND BOX can be used roughly.
In real time, you can find any one of the above scenario in the Project, and it may be something different also.
Next time when you face the question, explain the system landscape in your current project? Don’t worry; you can explain any one of the above scenarios.