How To Build A Shelf With PET Bottles

Hi all Steemians,
Hope you are having a good weekend.
I wanted to share with you a design I came up with sometime ago. I think I read somewhere that everyday 100 million plastic bottles are used each day, that is absolutely crazy, and I don't even want to know the statistics of how many of these bottles end up in the ocean or that is discarded through burning. It's a huge problem as plastic takes forever to decay and if it enters the natural food chain it can do great damage to many animals and of course also to us humans!
So with that in mind I wanted to come up with an idea of how we can utilize these bottles instead of discarding them. The idea I came up with is to use the bottles to make a shelf. The bottles become the wall of the shelf and the construction is actually very simple. All you need is a board. On the top of the board you drill circles with a little bit bigger diameter then the bottles and these cavities can help keep the bottles in the right place and prevent it from sliding off the board. On the bottom of the board you make a hole that is just big enough for the cap to fit. Glue the caps of four bottles in this bottom holes and now you have made yourself a building block.
Below is a picture that show how you then connect the bottles with the board, and each layer is made in the same way.

So now you are probably wondering if these bottles can really carry this kind of weight, and the solution is to fill each bottle to the top with either water or sand, when compressed the pressure will now be equally divided on the bottle, and the water will prevent the bottles to fold. Granted you should not climb on this shelf !

So next time you have bottles laying around and you feel like you have some spare time why not build a shelf instead of throwing the bottles away? Looking forward to hear your comments !