An assembly includes a plurality of shelving components and posts. The shelving components include a body, a male portion that extends from a first end of the body and a female portion that defines a void in an opposite, second end. The male portion is narrower and shorter than the body. The female portion is sized and shaped to receive the male portion of another shelving component. The shelving components also include first apertures defined by and extending through the male portion, and second apertures defined by and extending through the female portion. The posts are sized and shaped to be inserted into overlapping apertures of first and second shelving components, the overlapping apertures comprising (i) a first aperture in a male portion of the first component inserted into a female portion of the second component and (ii) a second aperture in the female portion of the second component.

A stair tread cover suitable for covering at least one step in a staircase. The stair tread cover includes at least a front portion and a back portion. The front and back portion each have a top surface and a bottom surface. At least one friction region is optionally positioned on the bottom surface of the front portion of the stair tread cover, and at least one gripping region is optionally positioned on the top surface of the front portion of the stair tread cover.

An assembly includes a plurality of shelving components and posts. The shelving components include a body, a male portion that extends from a first end of the body and a female portion that defines a void in an opposite, second end. The male portion is narrower and shorter than the body. The female portion is sized and shaped to receive the male portion of another shelving component. The shelving components also include first apertures defined by and extending through the male portion, and second apertures defined by and extending through the female portion. The posts are sized and shaped to be inserted into overlapping apertures of first and second shelving components, the overlapping apertures comprising (i) a first aperture in a male portion of the first component inserted into a female portion of the second component and (ii) a second aperture in the female portion of the second component.

A tread for a steel-pan staircase. The tread includes a lattice structure comprising a top side, a left side, and a right side. The tread further includes a top surface integrally formed on the top side of the lattice structure, a first tongue-and-groove structure disposed on the left side of the lattice structure, and a second tongue-and-groove structure disposed on the right side of the lattice structure. The lattice structure comprises a plurality of lateral members and a plurality of crosswise members. The first tongue-in-groove structure may include a wall descending from the top surface. The second tongue-in-groove structure may include a first wall extending outwardly from the right side of the lattice structure. Extending upwardly from the first wall may be a second wall or a plurality of teeth. The placement of the first and second tongue-in-groove structures may be reversed.