T-square vs straightedge

T-square

noun
  • A rule with a short perpendicular crosspiece at one end, used by draughtsmen to draw parallel lines. 

  • A sex position whereby the receiving partner lies on the back with knees up and legs apart while the penetrating partner lies on either side perpendicular to the receiver, with the penetrating partner's hips under the arch formed by receiver's legs. 

straightedge

noun
  • A flat, rectangular tool used to draw, cut or check the straightness of straight lines. 

adj
  • Living one's life opposing or eschewing the use of substances such as alcohol, tobacco, and drugs. 

How often have the words T-square and straightedge occurred in a corpus of books? (source: Google Ngram Viewer )