Adobe Photoshop/Clone Stamp Tool
With the clone stamp tool you can pick up (or clone) a sample area of an image and copy it to another part of the image. For example you can copy an area of sky and lay it over a cable in your image, thereby causing the cable to disappear. Place the cursor on the area you wish to copy from, hold down ALT, and click. You have selected the area to copy from. Now move the cursor to the area you wish to paint over. Left click and hold and paint over the area you wish cover.