Two Expression 4s
Two Expression 4s operate the same way, which makes for easy understanding and a shared blind spot in the same place. Here is how it tends to go.
How Expression 4 and 4 get along
The house has too many load-bearing walls. Both of you behave with discipline, consistency, and a deep respect for doing things properly. The shared reliability is extraordinary, nothing falls through the cracks. The cost is that neither of you is wired to suggest tearing something down and starting over, even when that's exactly what's needed.
The two on their own
Compatibility starts with each number in its own right. Read Expression 4 first, then come back to how they meet.
Compare your actual charts
Two people are more than one number each. Your Expression numbers set part of the tone, but the rest of both charts and your timing shape the whole. Compare your full charts to see all of it at once.