How do the instrumentalists execute a strong backbeat in bluegrass music?

It's all about the strum patterns. Bluegrass instrumental techniques are very choppy and have more rhythm than flow. 

Analysis of da vinci's vitruvian man. another of da vinci's most famous works is that of the vitruvian man, created around 1490. the official title of the drawing is “le proporzioni del corpo umano secondo vitruvio,” or “the proportions of the human body according to vitruvius.”