Cut one 36 in. (91.5 cm) length of yarn and set aside for wrap. Wrap remaining yarn around the long side of the cardboard as many times as desired.
Leaving ends long enough to tie, cut yarn, then tie the beginning and ending yarn tails together.
Keeping all strands held together in one hand, slip cardboard out.
Pull strands taut using both hands and twist to desired tightness.
With the yarn length you set aside, connect the opposite ends of the twisted strands by wrapping through the loopholes on each end.
Tie the beginning and ending yarn tails together and trim. Bury tails, and secure with needle and thread.