bearisgray

It looks like 3 of the 4 sides are okay enough -

When sewing the side triangle units on to the center square - did you remember to have "dog ears" sticking out on the sides? (Scan attaches to illustrate)

For me - I have found cutting the center square with the grain line running from opposite corners gives a nicer finish - all the grain lines will be perpendicular to the edges when the unit is finished. (Also illustrated in scan.)