Variations on a Rectangle

Suddenly I have seen several sweater designs based on rectangles.  

This one, for example, is
a 6-foot scarf, about 20 inches wide,
worked in a lacy-kind-of-entrelac stitch.
The short ends were sewn together to make a tube,
then ribbing was added on one side to make a neck,
and on the other side to make two cuffs and the lower edge ribbing.
I saw it in a store for about $30.  The pattern stitch and the concept both seems really cool, so I bought it (and took the ribbing all undone).  The shape was not particularly wearable - there is no underarm sleeve length, but we're talking about the idea, here.

Then recently, a friend described another sweater made from a similar rectangular tube:  on one open side, mark a space for an arm opening,
then sew a bit for a shoulder,
leaving an opening for the neck.
On the other open side, mark a space for the other arm opening on the opposite side,
then sew a bit for a side seam,
leaving an opening for the lower edge.
Using the undone ribbing yarn from the store-bought sweater, I crocheted in a ch-2 net stitch to add to the two open sides to add width, and ended up with this:

And finally, a local yarn shop offered a kit for a rectangle pullover with dolman sleeves.  The pattern calls for knitting it in a 1x1 rib, but I will most likely crochet it in a ch-2 net stitch.  The kit should come in in a couple of weeks.

I like the idea of making things from simple shapes, especially if they work.  But even if they don't work, starting with a simple shape leads to understanding how shaping can make really good sense.