How to crochet a large circle into a square/rectangle

[ThursdayNextIsMyHero]

Hi, I started crocheting a while ago, and so far have done a couple of small projects, and a couple of blankets from Attic24s patterns - I love the colourways and find Lucy's patterns easy to follow. I'd like to make a blanket for my ds, who loves Avengers, and like the idea of making a rectangular Captain America blanket for him, with a round shield in the middle. I've found some patterns on the internet with the round shield, but they are round blankets, and I'd prefer to make a rectangular blanket, big enough to go on his bed. I can find advice on the internet on how to crochet small round patterns into a square, and have previously made Attic24's sunny granny blanket, which has a circular motif inside of a square at the centre of each block. However I have no idea of how to go about upsizing this. I've found a picture of a similar blanket on pinterest, except that it is square rather than rectangular, but I can't find a pattern. The person who made it had previously commented that they'd just made it from scratch.

Can anyone help, or give me ideas on how to do this?

Not sure if this link will work homemadeatmyplace.blogspot.co.uk/2014/09/make-it-crochet-circle-in-rectangle.html. I googled turn a crochet circle into a rectangle and this came up.

Thanks for the link, that looks useful for a rectangle, but I don't know how to size it up appropriately. Looking at the height of the stitches immediately outside the circle, I'm not sure how to translate it to a larger circle. If I'd like the blanket to end up at least 1 metre wide, the circle would need a diameter of at least 50 cm (have not tried sketching this out, so measurents are extremely approximate). The large circle in a square pattern, that your link is based on, is only 7 rounds, so still relatively small.

I wish I knew the answer, I'm just marking my place.

Have you got a link to the Pinterest picture?

Off the top of my head, I would envisage doing a circle and then join on separate shaped pieces for the corners. Once it was square, I would crochet round the whole lot. For a rectangle, you'd then have to crochet some rows top and bottom to lengthen the circle-in-a-square and add a border.

Sorry for the delay - I couldn't get to a computer over the weekend, and haven't attached a link or picture before and didn't want to try on my phone. The link (should be) s-media-cache-ak0.pinimg.com/originals/14/12/09/1412096592ea1d894023276e7b4ba1c2.jpg

I think that's been done poorly. The circle has been pulled out into a sort of rounded square - which is absolutely fine if that's what you want!

(Please tell me I've not just insulted your work!)

That's not my work , but it's the closest thing I could find for what I want to do. Pinterest has lots of round shield blankets/playmats and I've found the patterns for those. But I'd like to end up with a rectangular blanket with the round motif in the middle.

I don't like the way the one showed had been pulled out of shape.

I think the problem is that it would take a good number of rows to square off a decent sized circle in the same way the smaller ones are done. Basically you mark where the four corner points of the circle will be, where the four mid points between these corners are and gradually increase the height of the stitches between mid point and corner and then decrease them from corner to the next mid point.

It would take a while before you'd square off a bed sized blanket that way I think and there would be some trial and error to get the proportions right. I do think it is doable though.

If you have a look at 'Sophie's universe' on the 'look at what I made' blog that is a circle then a square. It was a CAL so should have a point where it changed and that should give you an idea? Otherwise there is a captain America afghan pattern on ravelry if it helps? I can't link now but will come back if you can't find it. I would start with the blog, the instruction videos are fab and I'm
Sure you can get an idea for your own blanket.