Yarn:
4 x 50 g balls of yarn in main colour, and
1 x 50 g in contrasting colour.

Additional items:
3 flat white buttons (4 cm diameter)
41 cm square cushion pad.

From the pattern description:

This eye-catching cushion has bold white polka dots against a bright blue background. Knitted in stocking stitch, the back is in plain blue with a buttoned opening.

The fabric is simple stocking stitch but the spots are worked from a chart using the intarsia technique.