Step 8: Turn The "Vertical Strips" Layer Back On

We're going to do the same thing now to create our vertical strips. First, click on the top "Vertical Strips" layer in the Layers palette to select it, then click back on its layer visibility icon to bring back the eyeball and turn the layer itself back on:

Step 9: Drag Out A Series Of Vertical Selections

Just as we did when creating the horizontal strips, let's drag out a series of selections, this time vertical ones. We'll make the vertical selections two grid columns wide, leaving one grid column between them. Use your Rectangular Marquee Tool to drag out your first selection, then hold down Shift and drag out the rest of your selections. Your image should now look like this:

Step 10: Add A Layer Mask

With our vertical selections in place, click on the Layer Mask icon at the bottom of the Layers palette:

Photoshop adds a layer mask to the layer and just as before, it uses our selections to determine which areas of the layer remain visible and which ones disappear from view. The areas inside our selections remain visible, and the areas that were inside the grid columns separating our selections disappear revealing both the "Horizontal Strips" layer and the black-filled layer below:

Once again I'll turn off my grid temporarily with Ctrl+' (Win) / Command+' (Mac) so we can see the image itself more easily. Your image should now look something like this: