Entrelac knitting

Arrows on the diagram indicate the knitting direction.
Increases 2 and 3 are repeated until the desired length of the piece is reached, noting that before the final fragment of triangles (4) increases 2 are performed.

1. Beginning of knitting. Row of triangles
* Cast on with light yarn 2 stitches.
1st row - purl stitches; 2nd row - knit stitches; 3rd row - purl stitches.
4th row (knit) - before the last stitch from the left edge, increase by 1 twisted knit stitch from the chain.
5th and subsequent purl rows are worked as purl stitches.
6th and subsequent knit rows are worked as 4th.
Increases should be made until there are 10 stitches on the needle. The 1st triangle ends with a knit stitch.*
Between ** repeat until the necessary number of triangles is connected. Cut the yarn.

2. Left edge triangle
Cast on 2 stitches with dark yarn onto the needle with the connected light triangles
1st row - purl stitches (purl row)
2nd row - knit stitches (knit row)
Then knit, joining the dark triangle with the light one.
3rd row (purl row) the last dark stitch and the first light stitch of the last triangle of the initial fragment knit together purlwise.
4th row the first stitch be slipped as for purling. Before the last stitch from the left edge increase 1 twisted knit stitch *.
Between ** repeat 7 times = 10 stitches. In the next purl row the last dark stitch and the 2 remaining light stitches knit together purlwise.

3. Dark square
1st row (purl) from the side edge of the light triangle, to form the corresponding square, pick up 10 stitches. To do this, with the left needle catch the front strand of the last stitch and purl it.
2nd row (knit) knit stitches.
3rd row (purl) * the last dark stitch and the first light stitch of the next light triangle knit together purlwise.
4th row (knit) slip the 1st stitch as for purling, and knit the remaining stitches. Repeat between ** seven times.
19th row: the last dark stitch and the remaining 2 light stitches knit together purlwise.

4. Right edge triangle
1st row from the side edge of the last triangle, knit stitches as described for the dark square.
2nd row - knit stitches.
3rd row - purl stitches.
4th row. from the right edge, knit the 1st and 2nd stitches together with a left-leaning decrease until only 3 stitches remain. Then repeat in every knit row. In the last knit row, slip the 1st stitch, knit the next 2 stitches together and pass the slipped stitch over it. Cut the yarn and pull through the last stitch.

Light square
1st row from the side edge of the dark triangle, corresponding to the square, pick up 10 stitches. To do this, with the left needle catch the upper edge of each last stitch and knit it.
2nd row - purl.
3rd row - the last light stitch and the first dark stitch of the next triangle knit together with a left-leaning decrease.
4th row - slip the first stitch as for purling, the remaining stitches purl.
Repeat this decrease 7 times. For the final decrease, knit the remaining 2 dark stitches together and pass the slipped light stitch over.

Then continue knitting, repeating dark and light squares as described above until the required height of the piece is reached.

Finish with a row of light triangles.

Light upper triangle
The first 2 rows are done as described above.
3rd row: the first 2 stitches together with a left-leaning decrease; join the triangle to the dark square from the left edge as described above.
Make decreases at the start and end of every right-side row seven more times.
When 4 stitches remain on the needle (2 light and 2 dark), knit them as follows: slip the 2 light stitches together purlwise, knit the 2 dark stitches together and pass the slipped light stitches over the created stitch.
For the remaining triangles in the initial row, knit only 9 stitches, plus 1 stitch left from the previous triangle.