When stripes, curves, or figures filled with alternating black and white lines join up so that every black line of one figure meets a white line of another, the eye of the viewer creates a new line—either straight or curved, depending on how the artist fits the figures together. Victor Vasarely (1906–1997) used this effect in his Bora series in 1964.

For this sock design, named after Victor Vasarely’s Bora series, I worked the pattern in knit and purl stitches, making the pair quite easy to knit. You can learn how to read charts en passant and create a stunning bit of op art for your feet!

Sizes: About 7½ (8)“ (19 20.5 cm) foot circumference, unstretched, and 9¾ (11)” (25 28 cm) foot length from back of heel to tip of toe. To fit U.S. women’s shoe sizes 8–9 (men’s U.S. shoe sizes 10½–11½); European shoe sizes 39–41 (45–46).