18 month old builds blocks in patterns

[ProfessorPickles]

Hello, I'm just looking for some advice really.
Both yesterday and today my 18 month old DS has been playing with giant Lego blocks and the arrangement doesn't seem to be random he seems to seek out other blocks of the same colour.
I can't upload pictures from my phone but just now he made a tower that went green, green, green, green, blue, blue, red, red.

And he did one that went green, blue, blue, green, blue, green.

I've heard this can be a sign of autism?
Is there anything else I should be looking out for?

My daughter is 14 months and built mega blocks in a pattern like a little wall with red yellow red on top and yellow red yellow alternating underneath - I just thought how clever, but only in the way I think everything she does is 'clever' I didn't think it was that unusual, maybe just slightly advanced. Her brother couldn't do it at that age but then he was obsessed with spinning wheels, and other things that I worried about. These have tamed a little over time and he is a lot more regular in his play at nearly 4 than he was at 18 months!

Have you any other concerns? I wouldn't have thought this was the basis of anything to worry about, they're exploring and learning all the time. A lot small children go through phases of obsession with a different thing, or type of play, think it's called a schema - I guess that's why they don't diagnose these things until later. Would be interested to see other responses though, I have no specialist knowledge.

I doubt it's a sign of autism. It actually sounds normal to me. My DS went through a phase of doing this with blocks, but plays more widely with them now.

Are there other things your baby does that makes you worry about autism?

I suppose he is pointing, walking, trying to communicate with you and such, otherwise you would have posted about those things?

This is called a schema, it's perfectly normal, it's how children up to about 4 make sense of objects and the world around them.

DD did this for a while, usually alternating colours or all one colour, but a few months later and she builds differently with them now. Perhaps matching up colours is the easiest and most entertaining way to play with blocks before they are able to build more complex things. I wouldn't worry about autism from one thing, are there other reasons you are wondering about autism?

Sounds perfectly normal to me. Just use it as an opportunity to talk to him about colours.

Thank you all for your posts, it is good to hear that it is a phase that is expected for them to go through!
The only other worry that I had was that he seems very sensitive to loud noises and I have an eating disorder that is often linked to autism so I was putting these things together in my head that probably aren't even issues.
I will definitely use it as a way to talk about colours

Our DS may have been a bit older, nearer two; he got hold of our coloured plastic clothes pegs, and arranged them all in batches of the same colour together.

Shows he pretty clever, I would have thought.

Just seen the sensitive hearing thing - my ds had a terrible aversion to loud noises at that age, alarms, sirens and hand driers etc would make him jump out of his skin/cry. Again, it seems to be something he has grown out of a bit, there is still a sensitivity there, but he seems to have adapted more. The other day he aurally used a hand drier for the first time and it was a big moment - he was very proud of himself