Hold the ALT and Shift keys and drag a duplicate of the wavy line vertically down the artboard then with both lines selected go to Object > Blend > Make. Tip #3: Capitalize on current trends. It’s obvious why a responsive screen mockup would be in demand; it’s a current trend and there are many designers jumping on that band wagon. Using our example above, what did the designer sell? A responsive screen mockup pack. The typefaces aren’t exactly proper, especially on the property cards. Use Line for the Shape and 30 lines/inch for the frequency.