edits

threejs/lessons/threejs-primitives.md

@@ -29,7 +29,7 @@ primitives.
 Here we are extruding a heart shape. Note this is the basis
 for <code>TextBufferGeometry</code> and <code>TextGeometry</code> respectively.</div>
 <div data-primitive="IcosahedronBufferGeometry">An icosahedron (20 sides)</div>
-<div data-primitive="LatheBufferGeometry">A shape generated by spinning a line</div>
+<div data-primitive="LatheBufferGeometry">A shape generated by spinning a line. Examples would lamps, bowling pins, candles, candle holders, wine glasses, drinking glasses, etc... You provide the 2d silhouette as series of points and then tell three.js how many subdivisions to make as it spins the silhouette around an axis.</div>
 <div data-primitive="OctahedronBufferGeometry">An Octahedron (8 sides)</div>
 <div data-primitive="ParametricBufferGeometry">A surface generated by providing a function that takes a 2d point from a grid and returns the corresponding 3d point.</div>
 <div data-primitive="PlaneBufferGeometry">A 2D plane</div>
@@ -74,7 +74,7 @@ based primitives easier to deal with.
 As an simple example a `BufferGeometry`
 can not have new vertices easily added. The number of vertices used is
 decided at creation time, storage is created, and then data for vertices
-are filled in. Where as for `Geometry` that is not true.
+are filled in. Where as for `Geometry` you can add vertices as you go.
 
 We'll go over creating custom geometry in another article. For now
 let's make an example creating each type of primitive. We'll start