For Isabella, the background reads plumb. The forground furniture piece reads as two rectangular boxes that should have the same vanishing point, but don’t. Also, the right part of the upper box reads plumb, the left tilts to the right. This all makes Isabella’s location and pose seem anatomically impossible and makes the painting seem unreal.

Another HH example of troubling use of linear perspective is the right-tilting walkway in The Importunate Neighbour and the unnecessarily intrusive and simplistic converging lines of perspective drawing in the wall and porch.

Finally, The Awakening Conscience always seemed off-kilter to me. Now I see this partly explained in the conflicting clues to perspective in the lines of the piano, the “too-sloped” floor and puzzling perspective clues defined in the mirror.

The composition of these paintings seem very elegant to me and not at all off-kilter, if one disregards 3D perspective. What’s off-kilter is coherently realistic representation of perspective.

It is conceivable that HH might have subordinated accurate perspective to the service of composition, I suppose. I would tend to see it as simply not being able to keep all the balls in the air.