A function with a lot of parameters or parameters with the same type can be confusing: ```typescript function cal(x: number, y: number, z: number) { return x * y + z; } ``` It is quite easy to call such a function with the wrong order of parameters. For instance: `cal(x, z, y)` Change the function to take an object, instead: ```typescript function cal(vars: {x: number, y: number, z: number} { return vars.x * vars.y + vars.z; } ``` The function call will look like: `cal({x: 1, y: 10, z: 3})` which makes it easier to spot mistakes and review code.