Becauserelativeposition, whenyouapply a topleftrightinbottom, itactuallytakesthatelementoutofthedocumentfloatandmovesitdownorleftorrightorupthose 10 pixelsthatyouspecified.
Andthereasonthatthiselementtwoandthreearenotactuallybeingpusheddownwhenthistopelementisbeingpusheddownisbecause, like I said, itwasremovedfromthedocumentafloatsoitnolongerworksjustlike a staticallypositionelement.