Gemini and Gemini share the air element: you meet in ideas. Conversation never runs out — plans, theories, inside jokes. The risk is living in your heads: this bond does well to ground things and say what's felt, not just what's thought.
Two mutable signs: infinite adaptation, mutating conversation, plans that change without drama. The hard part isn't getting along — it's deciding. This bond does well when someone says 'this, here, now' once in a while.