So, not sure exactly what is going on here but, if you have 3 (
Maybe more?) catapults lined up next to each other and just use one character to attack one, once it takes a % of damage just switch to the other(s) one by one and they will very quickly take a % of damage also. So, for example: I have 3 catapults lined up right next to each other. I am hitting on one of them and after like 4 minutes it takes a % of damage. I can now switch to the next in line or the one after it and start hitting it and in just a few whacks I get a % on it, then switch to the 3rd and again you get a very quick % damage to it... Now go back to the first and start hitting it again. In another roughly 4 minutes or so
(However long it takes does not seem to be connected to strength, as even with 3 characters of varying strengths attacking it at the same time, it did not seem to speed up 1 bit.) it takes a second % of damage. Now I just switch to the 2nd or 3rd in line and it will again almost instantly take it's 2nd % damage, switch over again to the 3rd now and..., rinse repeat, you are a catapult wrecking machine

It appears that there is some kind of 'area of effect' thing going on in regards to catapults taking damage and I'm not sure the range, or if this is just limited to catapults either.
So, some of the questions: 1) How many catapults can we line up and have this happen to each successive one further down the line..?
2) Do they have to be right next to i.e., touching, each other like these 3 were? I did notice that a battering ram about 15 tiles away seemed to not be affected by this.
3) Is this
only a 'Catapult' thing, or are other destroyable objects affected?