Kidney shape – make 2 for each kidney
Cast on 3
Row 1: Purl
Row 2: Knit, increasing in each end (5)
Row 3: Purl
Row 4: Knit, increasing at each end (7)
Row 5: Purl
Row 6: Knit, increasing at each end (9)
Row 7: Purl
Row 8: Knit
Row 9: Purl
Row 10: Increase in first stitch, knit to last 2 sts, k2tog (9)
Row 11: Purl
Row 12: Increase, knit to last 2 sts, k2tog (9)
Row 13: Purl
Row 14: Knit
Row 15: Purl
Row 16: K2tog, k to last st, increase (9)
Row 17: Purl
Row 18: K2tog, k to last st, increase (9)
Row 19: Purl
Row 20: Knit
Row 21: Purl
Row 22: K2tog, k to last 2 sts, k2tog (7)
Row 23: Purl
Row 24: K2tog, k to last 2 sts, k2tog (5)
Row 25: Purl
Row 26: K2tog, k to last 2 sts, k2tog (3)
Cast off purlwise, fasten off.
With wrong sides together, whipstitch around the edge and stuff.
Optional – leave one side open and add felt or fabric and a mesh to demonstrate filtration.