and that's one thing you could do with it:
It does involve a very impressive stitch combination ( page 123 bottom) but in real life it's quite easy, as the symbols have quite a clear logic.
The 'hook' symbol over 3 stiches, in row 17, will be the theme of the pattern and it goes like this:
drop the third st over the first 2 sts then k,yo,k. It is well described in the book.
Row 21, first grey block ( from right to left):
First start with an yo. What follows next is a decrease symbol: two lines merging : one line is the next st and the other is the stitch coming from the far end of the block, from pos. 5. So just slip the next st on the right needle, then save the next 3 sts on a cn at front and now, that we have access to the st in pos 5, slip the stitch from the right needle back and work a left slanted decrease. Next just work the 'hook' symbol using the 3 sts from the cn.
Row 21, second grey block ( from right to left):
Save the first st on cn at back (it will be used in the decrease later on). Work the 'hook' symbol as above, transfer the cn st back on the needle, right slated decrease, yo.
Row 25, first grey block ( from right to left):
Transfer 3 sts on cn, keep at front. Purl the next st ( see the little horizontal line? that's for 'purl'), then work the 'hook' symbol as above using the cn sts.
Row 25, second grey block ( from right to left):
One st on cn at back, the 'hook' symbol then purl the st from cn.