His paintings, influenced by Op Art, shows intersecting horizontal wedges of color.

On some stairs, both the vertical wedges that press against the risers and the horizontal wedges that press against the treads are accessible.

On some stairs, the vertical wedges behind the risers and the horizontal wedges beneath the treads are equally accessible.

On others, the horizontal wedges overlap the bottoms of the vertical ones.

With this arrangement, the wedges pressing against the risers can be tightened only after first removing the horizontal wedges beneath them.

The first modern breech-loading rifled gun is a breech-loader invented by Martin von Wahrendorff with a cylindrical breech plug secured by a horizontal wedge in 1837.

On others, the horizontal wedges overlap the bottoms of the vertical ones and have to be removed before the vertical wedges can be tightened.

On others, the horizontal wedges overlap the wide ends of the vertical wedges, as shown in the illustration.

Striking the ends of the horizontal wedges tightens both.

The triple tibial osteotomy involves removing a horizontal small wedge of bone (average 12 degrees) halfway along a vertical osteotomy in the tibial tuberosity.