Based on the maths of concentric circles, Concentricity is a fun beret to knit, and is simpler than it first appears. Worked almost entirely in rib, the pattern is worked top down and in the round.
Skills required: Knit & purl sts, knitting in the round, increases & decreases, specialist cast-on.
Gauge: 18 sts x 24 rows to 4in/10cm on 4.5mm needles over St.St. 17 sts x 28 rows to 4in/10cm on 4.5mm needles over Twisted Rib, lightly stretched