Shear Help...

Hi all!  Forgive me if the answer to this question is obvious, but I am literally in my first week of learning grasshopper and am hopelessly stuck...  I am trying to shear an object in the z axis, and have succeeded in creating the series of reference and target points, however, the object doesn't seem to be doing anything.  I have attached a screenshot and the definition (portion highlighted in green is the relevant operation...).  If anyone could give me some pointers that would be great!  Thank you in advance!