Trigonometry vest is knit in a few pieces with minor seaming in patchwork style
Instructions are written for 2 colors:
• Work main body flat up: 2 front panels (A&A1), 2 armhole shapings (B&B1), then finish back – C separately
• Block the pieces and seam part A and B are sewn first along the red line, then part C is sewn to part B along the yellow line, and only then part A and part C are sewn along the red line. Parts A1, B1 are mirrored, but knitted in the same way.
• Work the edgings (I-cord)

Yarn: sport-weight wool yarn (~350-375m/382-410yds per 100g/3.5oz) in 2 colors (see yardage below). Yardages per size are provided in the Sizing & Yardage table below.
The sample was knit in Zegna Baruffa (~1,500m/1,640yds per 3.5oz/100g) work holding 4 strands of yarn together.
Needles:
• Main (for the body): 3.5mm/US4 (or size to get gauge in garter) circulars on a 60 cm/24” cable;
• Smaller: 3mm/US2.5 (or ~0.5mm/1-2 sizes smaller than the main ones

GAUGE (MEASURED PER 10X10 CM/4X4” SQUARE AFTER WET BLOCKING)
• 24 stitches by 42 rows on main needles;

TECHNIQUES
• Working in garter stitch
• Reading charted instructions (optional)
• Decreases: slip-slip-knit (ssk)
• Increases: knit-front-back (KFB)
• Backwards Loop Cast-On video tutorial
• 3into1
• Chain selvage edges in garter
• Kitchener stitch/grafting garter fabric
• I-cord (bind-off) on 3 sts
• Tip on no-ladder bind-off