The discovery of how to knit a square this way  has resulted in many uses from a single 'building block' : dish/face cloth, tea towel, shawl, blanket,  hobo bag, cushion cover, portable project pocket, and using more than one square to make  a number of vests – and now – the yin yang jacket.

I named it a yin yang square because, on the diagonal, half is in stockingette stitch, the other half in reverse stockingette stitch so it resembles the yin yang symbol.  And I find it zen-like to knit, satisfying and soothing; quite life metaphorical.  Basically you start out with three stitches, work to a side length, reverse the stitches and begin to decrease to a final three stitches.  There's something whole-being-more-than-the-sum-of-its-parts about the steady -and quick – increase on four rows, the change of texture at mid-point, the rapid decreasing again on the four rows. 

What you do is CO 3 sts.  Row 1:  Inc 1 st K to end of row   Row 2:  Inc 1 st P to end of row  Row 3:  Inc 1 st. K to last st.  Inc 1 st.  Row 4:   Inc 1 st P to last st. Inc 1 st.  You are increasing six stitches on four rows. (This also makes it easy to figure out which row you are on if  you get distracted: I get easily distracted: just keep adding 6 to 3 – 9, 15, 21 etc.)

When the length of a side is as long as you want you begin to decrease but now work in reverse stockingette stitch like this  Row 1:  P2tog P to end of row  Row 2:   K2tog  K to end of  row  Row 3: P2tog  P to last 2 sts. P2tog  Row 4: K2tog K to last 2 sts. K2tog.  CO last 3 sts.

What I want to share is the Yin yang jacket. 
Here it is  (purple)  in a baby size with eleven  inch sides.

The black is for a toddler and has fourteen inch sides.

Each is made from four squares, front back and two sleeves.

In the purple I cast off a few stitches at the
half way point in the front and then cast them back on at  the next  row to give a front opening. 

The black has a boat neck as the front and back are interchangeable  so it can be worn either way.   What I did do here – and I plan to repeat it on another jacket – is I used larger needles for one square but still knit to the fourteen inch side, so I got a looser gauge on one side which can be either the back or the front.  I want to try this on an adult version; seems to me it will be interesting to wear a garment that drapes differently front or back (depending on which way it is being worn) and also will have a different degree of warmth; on somedays  I may want more density on my back or vice versa.

Both jackets  are joined with a simple running stitch.  The way the sleeves are folded and attached varies the textured pattern.

It's an architectural fit, housing the body;  however, it is versatile and could be made to be worn snugly.

You knit it to body dimensions, not a prescribed number of stitches; the type of yarn and size of needles is the governing factor.  Start with some nice yarn, knit a few rows in stockingette stitch with a size of needle that seems like it might suit,  look at the result and if a denser fabric is wanted,  go down a size or two of needle (continuing from the first swatch for comparison) or increase size of needles for a looser weave.  When you get the 'just right' combination of needle and fibre then frog the swatch and  start the yin yang square  knitting  until you get the length of the side (shoulder to waist and/or width across front/back).  There is a way to elongate from a square into a rectangle but for the moment I am focusing on a simply square garment.  I like the boxy look. 

I am working on the adult version and will post later.

Here six squares are joined to make a swaddling coat for an infant.  The bottom two squares can be removed (see the running stitches) and the top then used as a jacket.  The sleeves can be folded across the body and not used when swaddling is wanted.  It is cosy.