Stitchfinder: Knit Trim: Zig Zag Rib

Skill level: Easy 

Twisting two stitches on both right-side and wrong-side rows makes a strong zigzag ridge. 

Method 
Cast on 4 sts. 
1st row (RS) K 1, take right-hand needle to the back and k second st through the back of the loop, then k first st in the usual way, slip both sts off together, k 1. 
2nd row K 1, with yarn to the front miss first st and p second st, then p first st, slip both sts off together, k 1. 
Repeat 1st and 2nd rows. 
Bind off.