What characteristic describes something that is slanting or not straightforward?

The term that describes something slanting or not straightforward is "oblique." In both artistic and mathematical contexts, it conveys the idea of angles or positions that are not aligned vertically or horizontally, implying a certain degree of complexity or indirectness. In visual arts, oblique lines or forms can create dynamic compositions and add interest by challenging conventional perspectives.

In contrast, "alkyd" refers to a type of synthetic resin used in paint, known for its durability and quick drying properties, which does not relate to the notion of slanting or indirectness. "Tessellation" pertains to the covering of a surface with a pattern of one or more geometric shapes, fitting together without gaps or overlaps, and focuses on repetition and evenness rather than being slanting or indirect. "Scumbling" is a painting technique that involves applying a thin layer of lighter or opaque color over a dried layer, which again does not convey the characteristic of being slanting or not straightforward. Thus, "oblique" is the most fitting term in this context.