Widening Procedure by the Example of Single Jersey fabric

Widening onto an empty needle = tuck

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The widening by 1 needle can be executed at the left and right fabric selvedge in the same stitch row.

Widening by transferring stitches by one needle outward = pointelle (without closing)

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The hole (=pointelle) that resulted from transferring stitches outward (stitch group = widening width) can also be closed by knitting + transferring a tuck. (= Widening with Closing-Stitch)