Aim to be porous
Obviously, open by default is the new fashionable, but I'm pretty sure it's no longer enough for organisations to be "open" because no matter how hard you try, eventually that just becomes PR and marketing fluff. Much better to aim to be porous. For people and conversations and ideas to flow in and out irrespective of departmental and organisational boundaries. Rip down the barriers to conversation and collaboration internally and externally.