These items allow you to make a cave like environment which gives the game a whole new experience.
How to use these items:
Draw an outline of the cave with the items which can be found within the folder "CaveTerrain"
Delete the ground underneath the items to avoid dirt flickering. This block can be found at 10-3-1 in the editor
Go inside the cave and start to place the roof connectors to create a border and fill in any missing gap with the double sided dirt square. These items can be found in the "RoofConnector" folder.
Draw an outline around the cave interior. You can follow the black squares as a reference. The items can be found in the "ValleyHole" folder. Remove the ground to avoid flickering as in Step 2.
Final step is to fill in the holes on top of the cave. Place the double sided dirt block which is found inside the "RoofConnector" folder and place them on top without placing over the open hole.
All that is left now is to add blocks inside the cave, compute the shadows, validate and your all set.