The description on the package says the following:
UK fabric mix with pre-cut pieces of 100% cotton cloth, 12.5 x 12.5 cm (5x5"), 2 of each. Shrinkage is 6-7% selected colors and patterns in perfect harmony with each other Pack with 40 pieces.
See Tilda books and patterns for inspiration. These patterns and colors benefit greately from combination with off-white solid cotton, like Kona cotton from Robert Kaufman, color K001-1339 SNOW.