what you'll have to do is you'll have to do the green thing first and then in the next step you'll have to do the blue thing second and then so these are now pairwise routing between nodes but ultimately what an attention mechanism does is it does everything to everything right in a single layer it routes information from all the nodes to all the other nodes and to achieve that so you need multiple rounds of this and it turns out that in the worst case you actually need n rounds of this so you know you trade off your you go from