This top is very versatile and can be made in any size and use most any yarn. The pattern starts after working the size of the granny square needed to fit across chest and slightly wrap around side. I made a 2t size with worsted yarn and H hook.
Make 2 *front and back
Starting with a 9 row granny square.
Row 10..slip stitch to ch2 space, slip stitch in ch2 space 2x, ch2 2dc in the corner space work in pattern to 4th corner (leaving last side un-worked/neckline) work 3 dc in that corner.
Ch3 turn, work in pattern til you have 5/3dc groups ch2 turn hdc evenly across ending with 2hdc in the starting ch3 space. Ch2 turn repeat hdc row back down sleeve. Ch1 turn sc across working 2 sc in ch space below.
Work Sc evenly across top of granny square (this is the neck line)
Ch3 work granny pattern in next 4 ch1 spaces in 5th space 1 dc ch2 turn hdc evenly across working 2 hdc in ch3 space. Ch2 work hdc across. Ch1 turn sc across 2 sc in corner and sc across top til you reach sc worked for neckline. (about 5 sc) slip stitch and fasten off.
Repeat for back
You now just need to join them together. You can pretty much do this any way you like but I like to have a little give in between them so I have written up the way I like to do this. Hopefully it is not to confusing for you.
Joining side seams
Put right sides together. Starting with the top layer in the ch2 space of bottom corner. Make your starting loop pull through the top layer of ch2 space, Ch2 and slip stitch from front to back of bottom layer. *Yarn over and dc into the next stitch in the top layer. Then from front to back in the bottom layer insert hook and pull yarn through both loops on hook. Repeat from * Work up to the bottom sleeve seam then sc the two sleeves together and fasten off.
Repeat for other side seam.
Joining neck line..
Starting from top corner shoulder seam work the joins the same as side seam til a little after the sleeve for both side. (about 10-12 stitches)
Weave in all ends and turn right side out.
To finish it off I like to add a few rows of hdc (unjoined) to the front and back of the bottom edge
Hope you enjoy and please let me know if I forgot something or if you have any questions...:)