Several shapes can be combined (merged) into a single shape. The result is the logical union of the shapes. The combining of smaller obects together allows easier transformations, etc.

let newshape = union(square({size: 10}), cylinder({radius: 4, heigth: 12})

The CSG library functions can also be used. NOTE: Deprecated in the V2 API

sphere({r: 1, center: true}).union(cube({size: 1.5, center: true}))