|     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)


##</code><code>##

posture=2 (10)
app_width=5  (101)
structure=6  (00110)

then the bits should look like:
000000 00110 101 10
or, without the spaces:
0000000011010110

##</code><code>##

my $style_word=pack(b2 b3 b5 b6),$pos,$aw,$stru,0;