UPD: Overlay mosaic crochet files are available for free for members of my Facebook group. https://www.facebook.com/groups/345702437625205

Technic: Double filet crochet, Interlocking filet crochet
Type: Blanket / Afghan
Gauge: 5 windows by 5 windows in 5 cm
As long as your windows are square, using a different gauge won’t affect the design, but it will change the finish size and the amount of yarn needed.

Hook size 4.5 mm. Hook size needed to match the gauge.
Approximate yardage 4000 meters of yarn for each of your two colors, which is a total of 8000 meters of yarn. (4375 yards per colors, a total of 8750 yards of yarn). (18-19 skeins (3.5 oz) for each colors)

Size: 150 cm wide and 210 cm long (150 x 210 windows)

The pattern contains a graph and Right-Handed instructions.