About this image

I'm using my mod a.k.a. H's special things to get what you see. I have a 3 phase of invulnerable doors 1st intentionally open most of time to bait/trap zombies and 3rd is there just in case if i accidentally open 2nd.
The entrance hall I trapped zombies is made from invulnerable blocks from the mod, meaning they cant break in, so they are fish in the net, i just need to pull the trigger to get experience.
My base has 2nd entrance like that in case i wanna go out but do not interested to kill them (i can just shut the exterior door and trap them forever). Base also has 3rd exit on top to be safe in case if other entrance is also crawling.

Edit: Oh maybe you don't know but most important part here is the glass pillars i made, they allow me to see inside clearly + allow remote control the doors from behind (they don't require electricity and have range of 30 meters to remote control). (with iron bars etc. you can't remote open/close doors, this is not possible, it is only possible with little pillars).