The 1986 movie "Three Amigos" sees three out-of-work actors, played by Steve Martin, Chevy Chase and Martin Short, head to Mexico to play heroes, only to discover that everyone thinks they are real-life adventurers who are expected to save the day. The characters don distinctive outfits that make a great fancy-dress costume -- just be sure no one mistakes you for a real crime fighter while you are wearing it.
Cut the bottom off the suit jacket, so it is the length of a bolero and sits just above your waist. Sew this edge.
Use the fabric pen to draw an elaborate swirly pattern in a line along the centre of the left arm. Include loops as if you are drawing a coil. Draw two more patterns in a line either side of this one. Repeat on the right arm.
Draw a silver swirly pattern in a line vertically along the left and right lapels of the jacket. Add shorter swirly patterns at the side of the lapels on the bottom half of the jacket.
Draw a silver swirly line along the outer seam of the left leg of the trousers. Draw another line either side of this one. Repeat on the right leg.
Using the swirly pattern style, draw a silver eagle on the front of the sombrero.
Put on the shirt, trousers, jacket, shoes, belt, cummerbund and sombrero. Tie the scarf in a knot around your neck so the knot is in front of your neck and the two sides of the scarf fall either side.
If you want to add a gun to the costume, get a pretend gun and holster from a toy or fancy-dress store. Use an old suit or buy a second-hand one. Look at pictures from the movie for an idea of what the silver patterns look like.