Interestingly, at the time of development, the DirectX SDK had not been implemented for managed, or .NET Framework-based, code. As a result, the developers of Terrarium took advantage of COM Interop, a .NET Framework service used to tie into existing unmanaged code from within a .NET Framework-based application. The ability to call unmanaged code is a powerful one and can enable developers to leverage existing, legacy components as they go forward in their application development.