Sweater construction. The bottom body and sleeves are worked flat, sideways, stripe by stripe. Every detail is then seamed on the side. After that, live stitches are picked up along the top and everything is knit seamless, in-the-round.
Size: the detailed instructions in the PDF are for the size small only. Sweater measures 45cm wide between underarms and 60cm long from back neck to the bottom, without the zigzag edge.
Resizing can be done in the increments of 9cm. (one double stripe) and does not require any computation. Just knit the bottom long enough so that it comfortably wraps around the widest part of your body (or your arm) with some positive ease. Then follow the increases/ decreases algorithm in the pattern.

For other patterns using similar technique, look at Doodle-Noodle and Mirage.