¡Bueno! At the risk of opening another Dead bashing thread.... I was listening to a 1973 Eyes Of The World just now. Got to the long extended jams and I noticed NO ONE was playing the beat. Jerry was noodling as was Phil. Bobby comping on E and A of some flavor over and over ...drums and keyboards just floating along for the ride as usual but I started to listen and despite a cacophony when I lifted my ear I knew EXACTLY when the change would come and like a swiss watch they all nailed it and dove back into a structured rhythm..... Even if they were using visual cues I saw them pull this off on larger stages where they were pretty well separated so a wink and a nod not gonna be seen by entire band I almost got the feeling they were playing everything BUT the note they should have and let the absence of it, floating like a void, call the timing... What's weird is I could follow it. Despite being preoccupied and not really listening (perhaps that's part of it!) I sat there aware of this and followed for about 15 seconds and hit a chord at exactly the change as well..... There was nothing to count... Jerry's runs were loping right over any changes that should have been there...as was Phil.... I've listened to lots of jazz and even when it gets way out there they rely on drums of bass to be nailing the structure to the floor. Pretty wild to let the entire band improve and then not miss a beat.