2 string modes: Mixolydian

The Mixolydian mode as a pattern that repeats every 2 strings:




And here both of the above patterns are combined. The blue coloured notes are the 4th degrees of the scale, so typically you would play only one of each in a scale or arpeggio because they are the same notes (they're enharmonic):

As I stated a while ago, this is actually a feature of these 2 string modes—the 4th degree is immediately before/after the string crossing so you have the option to play it wherever it suits you.