I spoke about my joint work on incidence results for cubics with David Wehlau (Royal Military College of Canada) in Meera Sitharam's course at the Fields. I described a new incidence construction that checks whether 10 points lie on a cubic. In the meantime, I learned that Grassmann considered this question as well. I'll describe Grassmann's construction and show how it allows us to use a straightedge to find the third point of intersection of a line through two given points and the cubic through these two points and seven additional points.