Two Tone Bobble Square
I found it easiest to do this square with two balls of main colour and one of contrast. Twist yarn at colour changes to reduce the risk of holes.
k1B means knit 1 below.
Cast on as many stitches you like.
Knit 5 rows of garter stitch (knit every row) using main colour (MC)
Next row: Knit 5 using MC, join on contrast colour and [k1, k1B] repeat until last 5 stitches, join on second ball of MC and knit to end.
Next row: knit 5 using MC, change to contrast and knit to last 5 stitches, change to MC and knit to the end.
Next row: using MC knit 5, [k1B, k] repeat till last 5 stitches, knit to end.
Next row: using MC knit across the row.
Continue these rows until the desired length then change to MC and knit 5 rows garter stitch, cast off. Weave ends in.