My blanket is in an Alexa ad!
https://youtu.be/7F8wyAksCXw?si=lVVZdPYVVVlOUIPj

w/w yarn
Amount used: two full 7oz skeins of red -- includes the center block and the foundation round of the border.
About 1 1/2 skeins (so, roughly 10-12 oz) of the other colors.

I crochet hook, K tunisian hook

Check gauge. Make sure that your moss stitch gauge matches the row gauge of your Tunisian crochet.
Adjust hook sizes as needed.

Note: If you don’t like moss stitch, use something different for the center! Any pattern should work as long as it has equal number of stitches on all sides, evenly spaced stitches, spaces (e.g. ch2) at the corners, and the gauge matches your TSS. You can also change the size of the center square -- 21 stitches looked good to me, but there’s nothing crucial about that stitch count -- or use a rectangle. Just change the stitch counts accordingly.

CENTER: moss stitch square w/ I hook

special stitches/techniques:

-- MR: magic ring, aka magic circle, magic loop. Technique to start in-the-round work without leaving a hole in the center. https://www.thesprucecrafts.com/crochet-magic-circle-tuto...

-- alt-dc: My preferred way to start a round with something that resembles a dc better than ch2 or ch3. https://www.acrochetedsimplicity.com/how-to-crochet-alter....

-- split hdc corners: instead of ending each round with a ch2 and slip-stitching to the top of the first stitch made, I replace the (ch2, s/s) with a hdc. The result is that the working yarn is now at the middle of the corner space instead of the far side. That’s where we want it to be for starting the next round.

R1: into MR, alt-dc, 2 dc, (ch2, 3dc) x 3
hdc into first st (the alt-dc)

R2: sc in corner
< sc in dc, ch1, skip next dc, sc in last dc>
( sc, ch2, sc) in corner ch2 space
repeat twice more
repeat <> once more
sc in corner
hdc into first sc

R3: sc in corner
< sc in sc, ch 1, sk 1, sc in ch1 sp, ch 1, sk 1, sc in sc >
( sc, ch2, sc) in corner
repeat twice more
repeat <> once more
sc in corner
hdc into first sc

R4-9: repeat R3, adding a (ch1, sk1) per side each round

final stitch count per side:
11 sc, 8 ch1s and 2 corner spaces per side ===> 1st round of Tunisian will have 21 rows

SPIRAL: Tunisian “Twelve-Stitch” w/ K hook

Based on Dedri Uys’s Tunisian Ten-Stitch pattern https://lookatwhatimade.net/crafts/yarn/crochet/free-croc...

Segment 1, part 1:
First row, FP: Attach to ch2 corner of central square with a slip stitch. Chain 13. Pull up a loop in third stitch from hook and each stitch of the chain back to the central square. (12 loops on hook)
Pull up a loop in the ch2 corner (same place as your attaching slip stitch).
RP: (yo, pull through 2 lps) across.
subsequent rows FP: pull up loops in each vertical bar and in the next stitch or ch1-sp of center square (13 lps on hook). RP as above.

Complete 21 FP/RP rows. Last one should connect to the next ch2 corner of the center square. Do not bind off, just secure working loop. Repeat on other 3 sides of center square. NOTE: you’ll have two Tunisian rows connecting into each ch2 corner of the central square.

Segment 1, part 2:
Complete 12 more rows, connecting into the 11 stitches across the bottom of the next Tunisian strip (the first 11 stitches of its foundation chain) and the corner gap (formed by sts. 12 and 13 of its foundation chain). Secure working loop. Repeat for other three sides.

From here, it’s pretty much the same as the standard Tunisian Ten-Stitch. Work an ending corner, a beginning corner, and the next segment, and keep going until it’s almost the size you want. For a square blanket, work the same number of segments of all colors.

Don’t work a bind-off row on any segments. The blanket border forms the bind-off.

BORDER: Moss stitch, using the larger hook you used for the Tunisian spiral.

Base round: You can continue with the same yarn as your final Tunisian section, or switch to new yarn, depending on your color choices. Either way, start with one loop on your hook at a corner of the work. Work bind-off single-crochet stitches across the row you just completed. Continue working single crochets along the side of the next segment. Work (sc, ch2, sc) into the corner. Repeat all the way around. Hdc into the top of the first single crochet.

Moss stitch rounds:
http://everytrickonthehook.com/patterns-2/moss-stitch-bor..., starting with R2.
note: I used split hdc corners (described above) rather than ending with slip stitches as Polly has written

I did two rounds of each color, in the same sequence as in the main blanket.