What are the sizes for changing the middle of blankets to accommodate your needs? This article has the square version plus four other sizes common for babies, kids, and multiple bed sizes. Those in hospitals or seated positions such as wheelchairs must keep their legs warm.
I have provided a crochet diagram. Written instructions for the square version, initially supplied by Yarnspirations, are also included. The four rectangle swatches used Caron One Pound.
Even with a striping colour like Red Heart Super Saver Stripes, this type of stitch is fun to watch and see what happens.

This article features the Small Crochet Interlocking Shells perfect for Baby Blankets. Below is the medium-size, and the colour is changed every four rounds instead.

Sizing

Each size has been checked to see how it will grow. For example, the XL has to have a long enough centre so that when it grows outward, it can reach the width and length of a twin bed.
The square can be made as big as you need. Written instructions for this size are available here.

This size Small (with yellow centre) is the base for baby blankets, child-size blankets, teenager blankets, throws, queen-size with drape, and king-size for both mattress tops and drapes.
Medium (with blue centre) is for wheelchairs, baby blankets, child-size and teenager blankets.
Large (with green centre) is for child-size and teenager-sized blankets.
X-Large (with orange) is for twin-size, cribs, cradles and queen-size with no drape.

Square Size Version
Match the hook to the ball band recommendation if you prefer a square size. A free tutorial was included. The original square version was completed with Caron Chunky Cakes yarn.
Small Sizing
This size is very versatile in sizing.

Yarn Used In Sample
Caron One Pound (454g / 16 oz, 742 meters / 812 yards)
- A - Any Colour
- B - Any Colour
Use size 6 mm, U.S. J/10 crochet hook or size needed to obtain gauge.
Match the hook to the yarn ball band recommendation if substituting.
Gauge 13 sc and 14 rows = 4” [10 cm]
Abbreviations
- Approx = Approximately
- Beg = Beginning
- Ch(s) = Chain(s)
- Cont = Continue
- Corner st = (Vst, ch 3, vst) all in same st.
- Dc = Double crochet
- Pat = Pattern
- Prev = Previous
- Rep = Repeat
- Rnd(s) = Round(s)
- RS = Right side
- Sc = Single crochet
- Shell = 7 dc in same sp.
- Sk = Skip
- Sl st = Slip stitch
- St(s) = Stitch(es)
- Sp(s) = Space(es)
- Vst = (1 dc, ch 1, 1 dc) in same ch or st.
Instructions - Small Size
With A, ch 17 (multiples of 6 chs + 11).
1st rnd: Vst in the 5th ch from hook. Sk 4 chs, ch 1, 1 dc in next ch, vst in next ch, 1 dc in next ch. Sk 4 chs, ch 1, (Vst in last ch, ch 1) 3 times. Rotate the project to continue to work on the underside of the chain. Sk 4 chs, 1 dc in next ch, vst in the next, 1 dc in next ch. Sk 4 chs, ch 1, vst in next ch, ch 1, 1 dc in same st as the last vst. Ch 1, join with sl st to top of beg ch 3.
2nd rnd: Sl st to next ch-1 sp. Ch 1, 1 sc in same sp. (Shell into the ch-1 sp of next vst. 1 sc in next ch-1 sp.) 7 times. Shell into next ch-1 sp. Join with sl st to beg sc. Break A. 8 shells and 1 sc between each around.
3rd rnd: With B, join with sl st to same st as join. Ch 4 (counts as 1 dc and ch-1 sp), 1 dc in same st as join. Ch 3 - corner sp, vst into same st as join. Ch 5, (vst in next sc, ch 5) twice. Corner st in next sc. Ch 5. Corner st in next sc. Ch 5. (vst in next sc, ch 5) twice. Corner st in next sc. Ch 5. Join with sl st to 3rd ch of beg ch 4. 4 vsts on long sides and 2 vsts on the shorter sides.
4th rnd: Sl st to next ch-1 sp. Ch 3 (counts as dc), 6 dc in same ch-1 sp. 1 sc in ch-3 corner sp. Shell in next ch-1 sp. (Sc over the ch-5 of prev rnd in the 4th dc of the shell below, shell into next ch-1 sp) three times. 1 sc in ch-3 corner sp. Shell into next ch-1 sp, Sc over the ch-5 of prev rnd in the 4th dc of the shell below, shell into next ch-1 sp. 1 sc in ch-3 corner sp. Shell in next ch-1 sp. (Sc over the ch-5 of prev rnd in the 4th dc of the shell below, shell into next ch-1 sp) three times. 1 sc in ch-3 corner sp. Shell into next ch-1 sp. Sc over the ch-5 of prev rnd in the 4th dc of the shell below. Join with sl st to top of beg ch 3. Break B. 4 shells on long side, 2 shells on short side.
TIPS:
- The yarn must be stopped entirely and restarted again in the single in corner space to look consistent.
- Mark corner stitches with a stitch marker to make it easier to follow.
- In 5th round, we are skipping the shells and working with single crochet stitches only.
- The 5th and 6th rounds repeat the 3rd and 4th rounds. The rounds are getting bigger between corners. The 5th and 6th rounds do not show how many shells or vsts there are between corners, as the pattern will become obvious. Each time you repeat, you will have increased by 1 vest or shell per side.
5th rnd: With B, attach with sl st same st as join. Ch 4 (counts as 1 dc and ch-1 sp), 1 dc in same st as join. Ch 3 - corner sp, vst into same st as join. Ch 5, (vst in next sc, ch 5) Rep ( ) to corner st. Corner st in next corner sc. Ch 5. (Vst in next sc, ch 5). Rep ( ) to corner st. Corner st in next corner sc. Ch 5, (vst in next sc, ch 5). Rep ( ) to corner st. Corner st in next corner sc. Ch 5, (vst in next sc, ch 5) Rep ( ) to corner to beg ch 4. Join with sl st to 3rd ch of beg ch 4. 5 vsts on long sides and 3 vsts on the shorter sides.
6th rnd: Sl st to next ch-1 sp. Ch 3 (counts as dc), 6 dc in same ch-1 sp. 1 sc in ch-3 corner sp. Shell in next ch-1 sp. (Sc over the ch-5 of prev rnd in the 4th dc of the shell below, shell into next ch-1 sp). Rep ( ) to corner sp. 1 sc in ch-3 corner sp. Shell into next ch-1 sp, (Sc over the ch-5 of prev rnd in the 4th dc of the shell below, shell into next ch-1 sp). Rep ( ) to corner sp. 1 sc in ch-3 corner sp. Shell in next ch-1 sp. (Sc over the ch-5 of prev rnd in the 4th dc of the shell below, shell into next ch-1 sp). Rep ( ) to corner sp. 1 sc in ch-3 corner sp. Shell into next ch-1 sp. Sc over the ch-5 of prev rnd in the 4th dc of the shell below. Join with sl st to top of beg ch 3. Break B. 5 shells on long sides, 3 shells on short sides.
Rep 5th and 6th rounds until the desired size. Each colour is used for just two rounds before switching to the next.
The crochet diagram shows the small size. The red chain and double crochet are the repeating segments when the chain is longer for medium, large, and extra large.
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Crochet Diagram
This is the basic structure of the interlocking shell blankets. In red, you will see a repeating sequence. You can download this diagram for your reference. This is a small size, for example. The medium, large, and x-large versions, the chain and starting round 1 have a more extended centre, as shown in the tutorials below.

More Ideas
- Crochet Interlocking Beginner Pattern Tutorial
- Crochet Heart Mosaic Baby Blanket Pattern
- 31 Days of Hats Series - Day 6
Tutorials


Jen says
I started the large size....on the 1st round you forgot the begining()....and you repeat twice not once. When you finish that round you should join in the 3rd chain not the 4th so you have the ch 1 space to work into.
That's all I caught.
Well done!
Mikey says
Thank you. I have updated.
Melanie Raymond says
I'm always up for a new pattern. I tested the small version with some lightweight yarn. I really dislike finishing off, just to start again, so I played with slip stitching to the corner. At first I sl on back side and then I decided to hdc the first shell and then sl in the stitch to the corner after finishing the round. I like this way the best.
I also, tried this with cotton crochet thread (thinking of a tablecloth). The sl to the corner works for this thread too. Just a thought so you don't have to break yarn every other row. Thank you for all of your work.
Mikey says
Thank you for the suggestions.
Sandi Grandberry, PhD says
Mikey, I am testing the small sample. There is one place I found that was a little confusing. On the 3rd round after the repeat * to ** the instructions were not clear that I needed to do another corner st and ch5. I wrote out the instructions in bullet form to be sure I wasn't missing something, but it doesn't appear to tell you to do that. I have a hard time following written instructions, I am easily lost. So, I may be wrong. I found an app (yarn buddy) that has lines to keep me in place left-right, up-down.
Mikey says
Can you type out what you would change in that statement? I'm not sure I am following you.
Sandi Grandberry PhD says
3rd red: Ch4 (counts as 1 dc and ch1 sp, 1 dc in same st as join, ch 3, vet in same st as join. *Ch 5, (sk next 7 dc, vast in next sc, ch5) twice. Sk next 7 dc, corner st in next sc, sk next 7 dc, ch 5,** corner st in next sc. Repeat from * to ** once, CORNER ST, CHAIN 5. Join with sl st to 3rd ch of beg ch 4…..