A circle....

Today's 'square' is actually a circle:

A surprisingly simple pattern which produces a circle which will lay flat.....
Chain 4 and join with a slip stitch.
Chain 1, 12 half treble crochets in the ring, do not join as you want to create a continuous spiral.
Work 2 half treble crochets in each stitch from the previous round.
*1 half treble crochet in the next stitch, 2 half treble crochets in the next stitch, repeat from * all the way round.

*1 half treble crochet in each of the next 2 stitches, 2 half treble crochets in the next stitch, repeat from * all the way round.

*1 half treble crochet in the next 3 stitches, 2 half treble crochets in the next stitch, repeat from * all the way round.

Continue in this manner, adding one extra half treble crochet between the sets of 2 half treble crochets on each round. I found it useful to use a stitch marker to mark the first stitch in each round so I knew when to introduce the extra stitch. If you lose count you can count the number of rounds completed and this will tell you how many stitches each repeat needs.