fix slight grammatical error

"Examples would lamps, bowling pins..."  I assume this is meant to read "Examples would be: ...")

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. 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="LatheBufferGeometry">A shape generated by spinning a line. Examples would be: 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>