What is a type of tactile block designed to warn of specific hazards like steps and level crossings?

The correct answer is the type of tactile block known as "corduroy." This type of tactile block is specifically designed to alert individuals, particularly those who are visually impaired, to potential hazards such as steps or level crossings. The raised, textured pattern of corduroy tactile blocks provides a tactile signal that indicates a transition in the walking surface, warning pedestrians to proceed with caution.

In contrast, the other options do not serve the same specific purpose of hazard warning through tactile feedback. Tile and brick do not inherently possess the tactile qualities necessary for hazard recognition, and while sandstone can be used in various construction applications, it does not specifically function as a defined tactile warning system. Thus, corduroy blocks are uniquely suited for this task, emphasizing the importance of tactile elements in creating accessible environments.