Hello! This is Rusty here, with my first tutorial!
Some of you may of seen my recent build, and the floor is all reflective! And your like "How the..."

Well I'm here to tell you how in a short and simple tutorial!

STEP 1:
First of all, your going to need to change the glass textures from the default texturepack to be transparent, but not completly invisible [You can use Paint.NET or GIMP for this]

STEP 2:
Now you need to make your structure! For this example were going to use a simple 6x6x4 square room:

Now that we've built this room, we now can start to decorate inside! You should use blocks that can be eaisly mirrored or flipped.  When I say easily flipped, I mean blocks that look the same if they were upside down, or blocks that can be flipped upside down (Ex: Upside-down stairs).

IMPORTANT! When using lighting, it is important that you DON't use torches, they don't work, and if you do use them your build won't look reflected, it will just look very stupid...

STEP 3:
Now it's time to build underneath! Dig an area underneath what your building, an begin building the room Upside-down directly below the room (Be careful not to add two layers of glass, the floor for the top will be the same floor for the bottom.)

Say, for example, if we added a glow stone lamp to the top of the room, it might look like this-


If all goes well, it will look like you actually have reflected glass! Which I can imagine lot's of people will find use for.

I hope you enjoyed this tutorial! Use it for your builds and make epic things! Kk?

SIDE NOTE: I know, I know XD A bunch of people before me have probably already found this, but the point is this is how I would teach someone if I had to XD