This waistcoat pattern is also a workshop on how to knit and join single mitred squares in Patchwork/Domino knitting.
It is knitted in 2 shades of Lang Mille Colori, which is an Aran weight long colour change yarn. Both yarns are used in each square but the yarn used for the edgings is also used slightly more in each square.
On the front of the waistcoat the squares are worked in a 'diamond' shape but the back is worked in 2 panels with the the squares mitre pointing to centre back from each panel. The back panels and back and front pieces are joined with garter stitch allowing for adjustment of fit.
The original version of this waistcoat was knitted in handspun yarns so it can be knitted in a variety of yarns. The sizes change depending on the number of stitches in each square so this is another way to adjust the size of the garment.