* RHS of simple integers
* RHS of another SimdShape
-In the latter case, there are further subdivisions because
+In both cases, there are further subdivisions because
SimdShapes can be created as either fixed_width priority
or elwidths priority
* elwidths priority (fixed_width=None)
* equal (no) priority (both are given)
+## RHS simple integers
+
+## Arithmetic of two SimdShapes
+
With some thought it becomes clear that when performing operations
not involving elwidth priority should simply calculate a new fixed
width based on straight arithmetic on the LHS and RHS fixed width.