Sentence:  ...he looked up the uninteresting left road to the fortifications. It was new, long, white, regular, tapering to a vanishing point, like a lesson in perspective. ... Smaller and smaller she waned up the rigid <WSD>mathematical</WSD> road, still gazing at the soldier aloft, as Pierston gazed at her. 
Meaning of the word marked with <WSD> tags:  Of, or relating to mathematics