A version of the Mystery pattern by Emex modified to make wrong side rows all purl.
In the swatch I tried different ways of working the one to two increase in row 5. In this case I think it's best to knit into the back then the front of the stitch, which I did at the top of the swatch.
This is what irishlacenet suggests to make a symmetrical one to two increase. It looks good.
Shown with a cast-on count of 16 stitches.