title: Constraints to keep two variable-width views close together at the center of the superview
body: <p>I have two views side-by-side horizontally in a container view. They are 8 points apart, but have variable widths. I want to keep the center of the two views equal to the center of the container view, so that no matter the size of the container, the two views together are at in the center of the screen. </p>
  
  <p>My idea to achieve this is to create two horizontal constraints, one from the left edge of the container to the left edge of the first object, and the right edge of the second object to the right edge of the container. I would then make these two constraints equal to each other, but variable with the size of the container. Unfortunately, I can't find a way to do this. I can only figure out how to make constraints equal or greater/less than a particular value. Is there any way to do this?</p>