By Noel Randewich SAN FRANCISCO (Reuters) – In the shadow of Internet monoliths such as Facebook, Google and Twitter, its easy to forget that Silicon Valley got its start from hard-scrabble tinkerers building radios, microchips and other devices. 3D printer maker MakerBot Industries was sold for $400 million in 2013 to Stratasys Inc – just three years after it was cofounded by a former art teacher. All of them embody the growing focus on hardware and the so-called Maker movement sweeping northern California and, in a smaller way, Europe and other countries. Two and a half years ago when we were started, it was rough, said Jeremy Conrad, co-founder of Lemnos Labs, an incubator that provides funding, tools and guidance for startups working on physical products.