Thank you, Tatsiana, for another intriguing design!
Thank you for letting me be one of the testers!

My Fjell cardigan wasn’t completely finished after crocheting according to the pattern because I made it much longer and added a border all around it.

My Fjell Mosaic Cardigan 3XL:

Sleeve length: 38 cm including cuff
Body length : 63 cm from shoulder to bottom (according to the pattern), I’ll make it longer

Yarns:
Black hand-dyed (400 m / 100 g) 300 g
Black2 (350 m / 100 g) – up to length in the pattern, without border: 200 g - will be at least 400 g with border
Colored hand-dyed (420 m / 100 g) 300 g

Yarn amounts:
Short row part before yoke – 21 g A
Finished yoke (including short-row part): 153 g A, 100 g B
(3XL: 3 times 41-48 plus 41, 42)
(switched colors A and B after the upper yoke)
Upper body colorwork: 66 g A, 50 g B
Lower body to 31 cm: 187 g black2

Sleeve first colorwork: 19 g A, 11 g B
40 rounds A – 43 g
( 6th round and 6times every 5th round 2 decreases, plus 4 rounds,
Another decrease round before cuff, crocheting together every 5th and 6th stitch)
Cuff: 3 g A, 3 g B
(skipped rounds 11 and 12, made 3 rounds sc with A instead)

Totals (without switching colors, before elongation and border!):
A: 153 + 66 + 187 + 19 + 19 + 43 + 43 + 3 + 3 = 536 g = 2251 m
B: 100 + 50 + 11 + 11 + 3 + 3 = 178 g = 748 m

Added another 100+ g to the bottom, hdc between sts in rows = 294 g black2 on the bottom, length after sleeve division now 47 instead of 31 cm.

My border:
I’m going to make a border around the complete cardigan (bottom, front sides, neckline) mainly with black2, using the first part of the cuff mosaic pattern. on the upper colored part and neckline.
I won’t make buttonholes, I’ll close the cardigan with jersey snaps (made by Prym).

Started border at “underarm seam position” under right arm.

• hdcs bottom - made sc betw sts, every 9th bottom stitch 2 sc (= increases because of the gauge difference between hdc and sc).
• corner: 4 sc increased
• front side: (4 x 1 sc into row, 1 x 2 sc into row) repeat until mosaic pattern starts
• mosaic pattern: (4 x 1 sc per row, 1 x 1 sc for 2 rows) repeat until start of colored part before neckline
• colored part before neckline corner: (4 x 1 sc, 1 x 2 sc) into row
• corner to neckline: 4 sc incr
• neckline: 1 sc per st, betw sts
• other side of the cardigan: pick up sts mirrored, close round with sl st

WS row: sc in every sc, close round with slst

row 3: RS, bottom and most of the front sides work with black2 in sc, only around neckline and the small colored sides before neckline corner repeat cuff pattern row 1, work with 3 balls (black2, colored, black2),ch2 instead of ch1, close round with slst. Bottom corners: 4 sc incr, neckline corners (ch2, sc, ch2, sc) 2x in corner middle sts. Close rd with slst.

row 4: WS, mostly sc with black2, neckline: row 2 of the cuff pattern, ch2 instead of ch1. Close rd with slst.

row 5: RS, mostly sc with black2, bottom corners: make 4 incr.
neckline: black row, make complete row with ball 1 of black2, it’s row 3 of the cuff, but with ch2 instead of ch1. corner increases: 2 (mdc, ch2) into sc before the corner sc, 2 (mdc, ch2) into sc after the corner sc.

row 6: just a normal WS row, sc and around neckline as round 4 of the cuff pattern with ch2 instead of ch1.

row 7: mostly sc with black2, bottom corners 4 incr, neckline: row 5 cuff pattern, neckline corners: on both sides of the corner (mdc, ch1, mdc) in 1 space

row 8: nearly a normal WS row, sc and around neckline round 5 of the cuff pattern, ch1 over the ch1-sp at the neckline corners. Cut color B and 2nd ball of color A.

round 9: Mark beg of round. sc in every st. Bottom corners: 4 incr. Neckline corners: Make (mdc,sc,mec) in ch1-sps. Close round with slst. Fasten off.

Yarns used for the border:
1st ball black2 - 47 g = 165 m used
2nd ball black2 - 13 g = 46 m used
colored yarn - 8 g = 33 m used