Connected Trapdoors is an experimental resource pack that adds connected textures to spruce, birch, dark oak, and pale oak trapdoors.
Model
Some trapdoors do not use connected textures because the sides of the trapdoor are visible when looking through it. 
CTM
With connected textures, when placing two trapdoors directly infront of one another that are the same type, the sides of the trapdoor model will use its top texture because it is trying to connect. This is noticable on birch, dark oak, and pale oak trapdoors.
