|     Style MSB     |     Style LSB     |
|15               9 |       4        1 0|
-----------------------------------------
| reserved        |Structure|App wid|Pos|

So, reading from right to left,
bits 0 and 1 = Posture (poss values 0-3)
bits 2-4 = Appearance Width (0-7)
bits 5-9 = Structure (0-31)
bits 10-15 = Reserved (locked to value of 0)