Sinkhole urban areas due to water main breaks or sewer collapses when old pipes give way. They can also occur from the overpumping and extraction of groundwater and subsurface fluids. Sinkholes can also form when natural water-drainage patterns are changed and new water-diversion systems are developed. Some sinkholes form when the land surface is changed, such as when industrial and runoff-storage ponds are created; the substantial weight of the new material can trigger a collapse of the roof of an existing void or cavity in the subsurface, resulting in development of a sinkhole. Sinkholes tend to occur in karst landscapes. Karst
A Void a parody of "noir" and horror fiction, with many stylistic tricks, gags, plot twists, and a grim conclusion. On many occasions it implicitly talks about its own lipogrammatic limitation, highlighting its unusual syntax. "A Void"<nowiki>'</nowiki>s protagonists finally work out which symbol is missing, but find it a hazardous topic to discuss, as any who try to bypass this story's constraint risk dying. Philip Howard, writing a lipogrammatic appraisal of "A Void" in his column "Lost Words", said "This is a story chock-full of plots and sub-plots, of loops within loops, of trails in pursuit of trails, all of which allow