In literature, the Foil is a character type that used to highlight the qualities of the protagonist by highlighting a strong contrast. Arguably, the most famous foil of all times is Sancho Panza, the famous Don Quixote squire who continuously contrasts with the protagonist both morally and physically and serves as a constant reminder to Don Quixote’s mission. Notice that the foil is not necessarily a negative character.
Just like in literature, missions in startups are better described and accomplished when there is a Foil in the story. In this context, a foil can be a large competitor, a situation in the current macroeconomic context of a particular industry or even a type of customer. Regardless, by presenting the characteristics of your foil you will highlight the benefits and vision of your company, product or service. It’s not that hard, if you are working on something relevant just look around and you will find many many Foils