Calls for 100g aran-weight wool in each of 4 colors.

From the book:

The chevron has traditionally signified something important, whether status, as for a sergeant’s stripes, or a warning, as in road traffic signs. V-shaped chevron stripes are the theme for this bag, ultimately knitted on a circular needle to remind us of the signs on endless roundabouts, so common in Britain. With the bag you go round and round and round, but we don’t recommend that at roundabouts.