yeah they are, almost exactly. Theres 4 weeks between their birthdays. They get on OK most of the time. The big 3 all have similar interests, and although DS1 does find DS3 annoying at times, and they do fight (but no more than either of them do with ds2) they can be really good friends too.
The other night there was a big spider in the bedroom (the big 3 all share) right near DS3s bed. Now I know some of you girls live in places where the spiders so big I'd faint if I found one in my house, and can be dangerous too. But we don't get those here and this was huge for what we do commonly see.
Anyway DS3 started screaming and freaking out, and we heard DS1 shout "quick get on my bed!" went up to find ds1 poised ready to grab it. DH got rid of it but DS3 wouldn't sleep in his own bed, so had to go in the spare bunk (we have 2 sets of bunk beds ready for when DS4 needs a bed) when I went to check on them before I went to bed I found DS1 in the spare bed with DS3, both fast asleep. So DS3 must have still be scared and DS1 got in with him.
They all fight and argue at times, thats what siblings do, but they are very close as well, even when constantly bickering. If they think someone is picking on one of the others they go investigate. DS3 just started school and they have a buddy system where a year 6 child (10/11 years old) is buddied up with a reception year (4years old) to help them get used everything. DS3s buddy is a boy who is actually quite naughty and has a bit of a reputation. DS1 and 2 both separately went to make sure that DS3 was ok when they saw him with his buddy.
I think having another in between them keeps them closer, like they both share interests with DS2 which then joins their interests together iykwim.
I worry that with 3years 7 months between DS3 and DS4 that the others will all be close and off out doing their thing and DS4 will be stuck at home too young to join in, with the others not wanting to play his silly little kid games. Thats why I want another to come along quickly. I was hoping for DS4 to be somewhere between 18 months and 2.5 years when the next one came along. The others adjusted much quicker than DS3 did to being big brothers as well.