How to make low poly water?

Question

I'm creating a game in Unity3D and I'm using blender as my main modeling software, The problem here is that I don't know how to make a low poly water cube, I've seen that a lot of people makes this using a plane, but I need to make a cube, and I can´t find how to make this in blender render or in Unity without A package from Asset Store. It should look like this:

Answer 1

Rendered in LuxCoreRender just for fancy look.

I'm not sure which cube you are referring to, so I'll first send you to some fluid sim 101 and then I'll show you what have I used for this scene.

1. Blender Docs
2. Blender fluid simulation tutorial in one minute

Now you know how to make simple Fluid sim and here is how I've achieved this low poly look:

Domain:

I've used resolution - 24. You can tweak it as needed. Lower value = lower poly count.

Inflow Object (Cube):

Here I've changed only Inlfow Velocity to -5m/s on Z axis. To speed up fluid.

Cycles:

If you want to render it with Cycles you can use this material for Domain object. But if you are gonna to use it with Unity this is optional.