I am trying to create an autofill similar to below, essentially requiring excel to realise that every 3 cells down the row number being referenced increases by 10. I have tried but it does not seem to recognise the pattern. Is there any way around this? ='Book1'!$A1:$D17 ='Book1'!$A1:$D17 ='Book1'!$A1:$D17 ='Book1'!$A11:$D17 ='Book1'!$A11:$D17 ='Book1'!$A11:$D17 ='Book1'!$A21:$D17 ='Book1'!$A21:$D17 ='Book1'!$A21:$D17