--- title: Share dimensions between pattern parts --- When you have different pattern parts that look similar -- like the front and back of a garment -- you may find that there's a lot of dimensions shared between them. The example below is from Aaron where dimensions are shared between the back and front part. Aaron has a file called `shared.mjs` that looks like this: ```js export function dimensions(macro, points, sa) { macro('hd', { from: points.cfHem, to: points.hem, y: points.hem.y + sa * 2.5 + 15 }) // more dimensions here } ``` In both `front.mjs` and `back.mjs` we use this code to add these shared dimensions: ```js import { dimensions } from './shared' // ... if (paperless) { dimensions(macro, points, sa) // ... dimensions specific to this part } ```