I have chosen to change colours throughout as I like the effect but if you stick to one colour for the border and one colour for the fptr/bptr the basket weave effect would be more pronounced. It's up to you!
Row 75 (pale blue)
Ch3 , 1 tr in every stitch across
Row 76 ( blue)
This involves front and back post treble stitches (raised trebles) which we did back in Week 3. Don't forget there is my You Tube tutorial if you have forgotten how to do them.
Ch2, * 1fptr (front post treble) around each of next 3 trebles, 1bptr (back post treble) around each of next 3 trebles, repeat from * ending with a treble in to the turning chain.
So, here we go...YO and put hook around the post from the front to the back
Now YO and pull the loop back through
so you have 3 loops on the hook
Repeat this for the next 2 stitches
So you have worked 3 fptr in total
Ok, now we're going to work 3 bptr over the next 3 stitches...so, YO and put hook around the next treble FROM THE BACK TO THE FRONT
This is what it looks like just before you grab the yarn back through
Now grab the yarn ,
and pull the loop back through so you have 3 loops on the hook
then yo pull through 2
YO pull through last 2 loops ; 1 bptr made
Repeat over the next 2 stitches so you've worked 3 bptr in total
Now continue from * to the end, finishing with a treble in the last stitch.
Row 77 (Purple)
Ch2, * 1 bptr around the next 3 bptr,
1 fptr around each of the next 3 fptr. Repeat from * to end, finishing with a tr in the last stitch.
Row 78 ( blue)
Ch2, * 1 bptr around each of the next 3 bptr, 1 fptr around each of the next 3 fptr. Repeat from * ending with a tr in the last stitch.
Row 79 ( pale blue)
Ch2, * 1 fptr around each of the next 3 fptr, 1bptr around each of the next 3 bptr. Repeat from * ending with 1 tr in the last stitch.
Row 80 ( plum)
Ch3 , 1 tr in every stitch to the end.
Here's a wider shot to see more of it...if you wanted to do a few more rows you'd get more of the desired effect so it's up to you!