From the pattern description:
A mosaic-stitch pattern on a mid-weight blanket takes its cue from the traditional geometric weaving of Wales. Knit in ecru and charcoal shades of Rialto DK, it’s bordered by a generous garter-stitch.

Materials:
Ten 50g/1≥oz balls (each 106m/116yd) of Debbie Bliss/KFI
Rialto DK (extrafine merino) in Charcoal 33 and eight balls in Ecru 2
4mm (US 6) circular needle
Pair of 4mm (US 6) knitting needles