Task: Question Generation
Input (English): Passage: Boxwood is a dense hardwood with fine grain, resistant to splitting and chipping—ideal for wood carving. In the 16th century, woodcut blocks used for woodblock printing were usually made of boxwood. Uses for boxwood were similar to those for ivory in medieval carvings, but boxwood was a far less expensive option than ivory. Designs were overseen by master craftsmen who must have had access to prints and woodcuts of contemporary works of art, and who were apparently influenced by diptych and triptych panel paintings.Boxwood grows slowly, so the trunk remains fairly narrow, a fact that limits the size of any carvings made from any single piece. The wood assumes an even, soft and tactile surface if polished or frequently handled, such as was the case for prayer nuts. The wood loses its tactility when painted, explaining why most of the miniatures are in monochrome. Polychromy reduced the legibility of the carvings, "quite apart from the difficulty of effectively coloring such tiny and complex scenes" as the art historian Frits Scholten has noted.The tools used in production were similar to those used in the production of larger altarpieces; they included saws, planes, card scrapers, chisels, augers, braces, and gimlets. Wood was cut into the required dimensions as blocks, after which the joints were carved out. Prayer beads were turned on a lathe. The woodcutters carved a single block of boxwood into a sphere, cut it in half, hollowed it out, and attached a fastening hinge and carrying loops. The carvings in the interiors were typically made separately from the smaller hemispheres and later fitted onto an outer shell. In some cases, these wooden shells were placed in silver housing.
Because of the diminutive scale of the pieces, magnifying glasses were used in their production. The very small wood pieces were difficult to brace (hold in place) during carving. They were likely positioned on a bench, between two posts, so that they could be turned around. Domed spaces, intended to evoke church architecture, were drilled or carved, and these were divided using compasses and a straightedge into pie-shaped segments. A surface plane was established onto which the reliefs were added. These were created from multiple separate wood sheets, individually produced before being joined in layers. Major figures, usually saints, were carved from single blocks of wood. Relief components were either glued into prefixed niches, or they were bound with pegs, which were sometimes functional and obviously visible or implanted into the relief form. Because of this layered structure, they are often fragile.
Output (English): Why does the dense hardwood that was used for 16th-century woodcut blocks grow on a tree that has a fairly narrow trunk?