Here is a goal: How to fold a bedsheet?

How would you accomplish this goal?

Choices:
[a]. Hold a corner of the bedsheet in each hand, fold diagonally in half. Repeat this process until the sheet is folded to the adequate size for storage.;
[b]. Hold a corner of the bedsheet in each hand, fold vertically in half. Repeat this process until the sheet is folded to the adequate size for storage.;
[b].