If you focus on the fact that the most interesting apps are *connected* apps, and that the dynamics of network economies are still in play, you see this less as a replacement and more as an evolution.

As a replacement of valve number 1 with Red valve's Type a and pneumatic fail-safe system 700, valve number 3 has accomplished an improvement in the fluid dynamics of the system.

Trees replacement patterns could be classified into 4 groups according to quantitative dynamics of seedlings, saplings and trees in different gap stages.