One-Color Double Brioche Stitch
When working a brk2, there will be two stitches under one long yarnover; work both stitches under the yo then slide the yo off after 2nd st. The yo at the end of the row over the last two sts is difficult to knit under so let it drop off after first st is worked and knit last st without a yo.

Double Brioche – same on both sides

Cast on a multiple of 4 sts.
Set-Up Row: *sl2yo, k2; rep from *.
Row 1: *sl2yo, brk2; rep from *.
Repeat Row 1 only.

Double Stockinette Brioche Stitch
The columns of this stitch scrunch together, they are being forced together because of the crossing of the yarn overs in between. This becomes obvious when the stitch is worked on large needles as in the examples below.Double Stockinette Brioche – RS                                       Double Stockinette Brioche – WSRS – worked on large needles                                          WS – worked on large needles

Cast on a multiple of 4 sts.
Set-Up Row: *sl2yo, k2; rep from *.
Row 1: wyif, *sl2yo, brp2; rep from *.
Row 2: *sl2yo, brk2; rep from *.
Repeat Rows 1 and 2.

Two-Color Double Brioche Stitch
Use either circular or double-pointed needles to avoid having to cut threads.
My colors: LC = brown, DC = turquoise.Two-Color Double Brioche – LS                                         Two-Color Double Brioche – DS

Loosely cast on a multiple of 4 stitches with LC using circular or double-pointed needles. Do not turn, slide. Attach DC.
Set-Up Row: DS DC: *sl2yo, k2; rep from *. Turn work.
Row 1 LS LC: *sl2yo, brk2; rep from *. Do not turn, slide.
Row 1 LS DC: *brp2, sl2yo; rep from *. Turn work.
Row 2 DS LC: *brp2, sl2yo; rep from *. Do not turn, slide.
Row 2 DS DC: *sl2yo, brk2; rep from *. Turn work.
Repeat from Row 1 LS LC.

Three-Color Double Stockinette Brioche Stitch
Use either circular or double-pointed needles to avoid having to cut threads.You need to work a selvedge stitch in order to catch yarns at the edges. You might notice that “- Color shift -” has been written into the instructions. This is a warning that you will shift the colors by working either two color A rows right after one another or a color B and C row right after one another. As you can see in the photo, two brown rows (color A) sit on top of one another, then one yellow followed by one blue row.
My colors: color A = brown, color B = yellow and color C = turquoise.Three-Color Double Stockinette Brioche – RS                   Three-Color Double Stockinette Brioche – WS

Loosely cast on a multiple of 4 stitches + 2 (selvedge stitches) with color A using circular or double-pointed needles. 
Set-Up Row: WS color B: p1, *p2, sl2yo; rep from *, end with p1. Do not turn, slide.
Row 1 WS color A: k1, *sl2yo, brp2; rep from *, end with k1. Turn work.
Row 2 RS color C: k1, *sl2yo, brk2; rep from *, end with k1. Do not turn, slide.
– Color shift –
Row 3 RS color B: p1, *brk2, sl2yo; rep from *, end with p1. Do not turn, slide.
Row 4 RS color A:k1, *sl2yo, brk2; rep from *, end with k1. Turn work.
Row 5 WS color C: k1, yf, *sl2yo, brp2; rep from *, end with k1. Do not turn, slide.
Row 6 WS color A: p1, *brp2, sl2yo; rep from *, end with p1. Turn work.
– Color shift –
Row 7 RS color A: p1, *brk2, sl2yo; rep from *, end with p1. Turn work.
Row 8 WS color B: p1, *brp2, sl2yo; rep from *, end with p1. Do not turn, slide.
Repeat from Row 1 WS.