Both arrays are extended versions of the array illustrated in Figure 3, but the twisting of the helices is indicated. The array on the left contains an even number of half-turns between vertices, leading to an array that consists of molecular chain main, red circles linked to blue circles. The array on the right contains an odd number of half-turns between vertices, leading to an interwoven structure, blue chains going lower right to upper left, and red chains going lower left to upper right.