===== Anatomy of a Design =====

A JSCAD design (script) must have at least one function defined, the **main()** function, which must to return a shape.

<code javascript>
const { sphere } = require('@jscad/modeling').primitives

const main = () => {
  return sphere() // a single shape
}

module.exports = { main }
</code>

Or an array of shapes.

<code javascript>
const { cube, cylinder, sphere } = require('@jscad/modeling').primitives

const main () => {
  const a = cube()
  const b = sphere()
  const c = cylinder()
  return [a,b,c] // an array of shapes
}

module.exports = { main }
</code>

In addition, functions can be created to split the design into managable pieces, i.e. parts, etc.

<code javascript>
const { cube, sphere } = require('@jscad/modeling').primitives

const partA = (options) => { // called from main() below
  var shapes = []
  shapes.push( sphere() )
  shapes.push( cube(options) )
  return shapes
}

const main = () => {
  let list = partA({radius: 10})
  return list
}

module.exports = { main }
</code>

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