I don't have a photo but I'll try to describe it better.
Imagine a sheet of A4 paper. Take a pen or pencil and draw blobs of varying sizes on it, leaving gaps between them.
Now you have to draw a straight line from the top of the page to the bottom. But wait, the blob is in the way. So, draw around the blob, keeping the same distance away from the blob as you do from the edge of the paper. Go around the blob until the line is level with where you started and continue down the page. Now start a new line the same distance away from the first line. Keep the lines parallel all the way down. Go around all the blobs as you progress across the page.