OFFSET-STRIPE SWATCH / APPLICATION DRAFT
12 stitches x 10 rows. US single crochet, flat turned rows.
Not physically tested. This is a workplan for making and reviewing a sample.
A = sand, B = petrol. Screen shades are references, not yarn product codes.

SETUP
Chain 13 in A. Row 1: sc in second chain from hook and across (12 sc, all A).
Before Rows 2-10: ch 1, turn. The chain is not one of the 12 stitches.
Introduce B at the start of Row 2 with a tail to secure later; enclose its working strand from the first stitch. From then on, crochet around the unused strand with each stitch, including Row 10.
When changing colors, finish the last stitch of the old color by drawing the new color through the final two loops. This does not add a stitch.
Row 1 defines the right side. Follow the flat method cited in the article: unused strand toward you on wrong-side rows, away on right-side rows, then enclosed in the stitches.

ROW SEQUENCES IN WORKING ORDER (RIGHT-EDGE START)
Row 1: 12A (12 stitches)
Row 2: 2A · 4B · 6A (12 stitches)
Row 3: 6A · 4B · 2A (12 stitches)
Row 4: 4A · 4B · 4A (12 stitches)
Row 5: 4A · 4B · 4A (12 stitches)
Row 6: 6A · 4B · 2A (12 stitches)
Row 7: 2A · 4B · 6A (12 stitches)
Row 8: 4A · 4B · 4A (12 stitches)
Row 9: 4A · 4B · 4A (12 stitches)
Row 10: 12A (12 stitches)

CHART ROWS TOP TO BOTTOM, EACH SHOWN LEFT TO RIGHT
10: AAAAAAAAAAAA
 9: AAAABBBBAAAA
 8: AAAABBBBAAAA
 7: AAAAAABBBBAA
 6: AAAAAABBBBAA
 5: AAAABBBBAAAA
 4: AAAABBBBAAAA
 3: AABBBBAAAAAA
 2: AABBBBAAAAAA
 1: AAAAAAAAAAAA

AFTER ROW 10
Fasten off and weave in ends without drawing the edge inward.
Record the actual process before claiming a tested result.

MAKING RECORD
Maker / date:
Yarn A and B, fiber and thickness:
Hook:
Actual starting/turning/carrying method:
Row 3 observation:
Row 7 observation:
Actual row counts and any corrections:
Front and back photo filenames:
Before/after finishing photo filenames:
Actual dimensions, if recorded:
Experienced reviewer and findings:

Do not infer a usable coaster, gauge, yarn consumption or physical behavior from the grid.