I'm building a spider spawner exp farm, and I have everything planned out.
Now the only thing is to build it. But what material should I use?
Are there any blocks that a spider (either type) just cannot hold on to the sides of?
My farm should function if there are none, but it would be a huge boost to convenience and efficiency if there are any such blocks.
Keep in mind that this question is not the same as this question which just asks how to make your house safe from spiders.