How to combine multiple textures in pixijs

Hi, I am writing a tile texture generator in which I need to stich 4 textures together, with multiple different combinations of textures.

Instead of making the sprites I want to pregenerate them by creating the combined textures together instead of having multiple sprites.

i saw that PIXI.RenderTexture was recommended, but reading the documentation doesn't seem to help, and I can't seem to get a working example. 

Included I created a fiddle, if someone can provide me with a working version, that is probably enough to get me going. 

https://www.pixiplayground.com/#/edit/joTwLMK7DcA0uek3o3MPe