Here is the pattern for my latest cushion cover. I used a 4mm hook and a blend of green and blue yarns
I use Stylecraft Special DK for most of my wools but occasionally mix in a Bonus DK
I found this pattern in a book that I have but it produced a much larger square so I fiddled about a bit and came up with one which I felt a better size. You could of course make yours bigger or smaller.
Start by making a foundation chain which can be divided into a multiple of 3 plus 3 extra
For example my square was 21 (7x3) plus3 = 24 chains
Miss the first 2 chains of the foundation chain (counts as 1dc) and stitch (1htr, 1tr) in next chain
(for those new to reading patterns anything you see in brackets you stitch together)
*miss 2ch, (1dc, 1htr, 1tr) in next ch *
repeat from * to * til you get to the last 3 chains. Miss 2ch, stitch 1dc in final chain and turn
(again for those new to crochet, anything you see in between asterix * follow the instructions til it tells you to as these are generally a way of not repeating everything several times over.
Ch1, (counts as 1dc)
(1htr, 1tr) in first stitch
*in next gap (1dc, 1htr, 1tr) *
*-* repeat til end
1dc in top of turning chain (tch) and turn
Repeat row 2 until you have your desired square or rectangle
Then sew squares together to fit cushion insert. Make it a tight fit or will go baggy.
I finished mine off with two purple edges which was just rows of 1dc to required width and then a mixture of blue and green buttons.