De Morgan's Laws
The negation of a conjunction is the disjunction of the negations.
The negation of a disjunction is the conjunction of the negations.
What do two algebraic rules have to do with socks? Without getting too heavy on the math, De Morgan’s laws have something to do with Heyting algebra, which is a bounded lattice.
These socks feature an interesting lattice cable, hence the foray into a mathematics lesson. The pattern is a top down construction with a gusset and heel flap. The ribbing yields to the cable pattern featured on the leg and instep. Above the heel and toe, the cable pattern transitions back to the ribbing.
The design is written to create the socks that appear in the first photograph. Additional instructions are provided to alter the placement of the cable charts to create the green socks.