We have defined a tangent as at least two images touching in a way that feels visually disturbing.  One of the most disturbing seen all too often in paintings is the "antler effect" tangent.  It looks something like this:

Whenever vertical shapes appear behind a horizontal shape, they can appear as if they are growing out of the horizontal shape, forming a kind of antler.  It's happening in this painting.

Tip:  To avoid the "antler effect", adjust the values between the vertical and horizontal objects so they don't contrast so much or insert other images between them.  

        Here's one way to resolve the above problem.

Here's the adjusted painting.