Fill cells skipping columns

at D1
=IF(MOD((COLUMN(A:A)+2),3)=0,INDEX($A1:$C1,D8),"")
copy from D1 To G1

what I mean is I want to use fillings with drag filling which is different from the lookup concept.
a simple example is like in the picture
btw thanks for the answer ghozi

screenshot => "drive.google.com/open?id=1q6MMkKFdwRrxvTGBFHSTSL9u_sKGNzhG"

Or better still following the yellow banner at the top of this page and giving us the data and the expected solution