Don't worry, I'll give you a formula,' Feluda reassured him. 'Double roles are very popular these days, aren't they?'It turned out that Lalmohan babu didn't even know what a double role was.'Sometimes, there are two heroes in a film, who look identical.''You mean twins?''Yes, they can be twins; or just two men who look similar, but are not related. They may look the same, but one of them is good, the other is evil. Or one is bold and strong, the other is meek and mild. Generally, that's what you'd find in a film. You could be a little different, and instead of having just one pair of twins, you could have two. Hero number one and villain number one could be the first pair; and hero number two and villain number two could be the second. At first, the audience need not be told about the second pair. It can be a secret. Then...'Lalmohan babu interrupted him. 'Wouldn't that make things far too complicated?'Feluda shook his head. 'You need enough material to last three hours. It's no longer fashionable to show a lot of violence, there are new rules about that. So you have to tell your story in a different way. You'll need an hour and a half to create a tangled web, and another hour and a half to straighten things out.''So all I need are these double roles?''No, there is more. Note it down.'Lalmohan babu fished out a red notebook and a golden pencil from his pocket.'Smuggling, you need smuggling,' Feluda went on, 'Gold, diamonds, ganja, charas -- it doesn't matter what it is. Then you need at least five songs. One of them should be devotional, that will be quite useful. You will also need a couple of dances, and two or three chase sequences during which at least one expensive car should be shown rolling down a hill. Then you must have a fire. The hero has to have a girlfriend, she'll be the heroine; the villain must have a girlfriend, too, except that she will be called a vamp. What else will you need? A police officer! Yes, a police officer with a strong sense of duty; flash-back for the hero; comic relief; quick changes in scenes and events, so that your story doesn't get boring. Also, it will help if the story can take the major characters to the sea or into the hills because it's not good for film stars to stay cooped inside a studio for very long... Did you get all that?'Lalmohan babu was still writing furiously. He nodded without pausing for a second.'Last, but not least -- in fact, this is most important -- you need a happy ending. However, if you can create tragic situations and jerk a few tears before the happy ending, it will work much better.