How to square a circle

I want to knit an afghan square where the center is a flat circle and one you reach about the size necessary of the square put corners or a square border around it. Does anyone have suggestions or know of a pattern that will give me directions?

Basically, your stitch count when you finish to the circle size you want should be able to be divided by 4. Concentrate increases at those four corners. Ideally, place markers before the center stitch of the corners and increase beside them. I did it with this pattern called Fluidity. It is lace so my increase sts were yos but M3 will do the same thing or M2 before and after that center stitch. This is available on Ravelry or Patternfish but may not suit.

You would do double increases where you want the 4 ‘corners’ on every other row. They can be K1, yo, K1 in one stitch, or kfb, kfb or m1, k1 m1 - whichever increase you want. And it needs to be done after you have maybe 4" knit at most, not when it gets to be the size you want, it won’t square up then.

The instruction mentioned below will work if the circle is to be about 2/3 of your total diameter or less. If you want the circle to be almost the full size of the square, short rows will need to be combined with the increases.

From this I would assume (always a bad activity) that you would divide the circle in to four section. Using a clock as reference, 12 to 3, 3 to 6, 6 to 9, and 9 to 12. Once the circle is as large as you want, short row between 12 and 3, increasing at the halfway point. turn and purl back to 12. Repeat, stopping one stitch shorter than the last row. Once the first corner is complete move to the second corner and repeat, until all for corners are complete. I would then consider one or two round around the outside to tie the square together then bind off.

Is this correct?