half drop repeat

To create this kind of a repeat (half drop repeat) I selected the secound column and went on View > Show > Grid, then to View > Snap to > Grid and draged the column down half a block.
I re-sized my marquie tool to 5cm-5cm that I can select one block. Then I copied and pasted it into a single gasp. After I did it to the forth column as well I went to Layer > Flatten image.