Image sampler only sampling in strips - .ghx included

Hello folks. I have a problem with using the image sampler module. I have a diagonal gradient for an image, yet my geometry only gets modified in linear "columns".

The goal of this fiile is to take an image representing solar insolation on a building facade, and use that data to drive the depth and rotation of louvers on the facade.

If you have any ideas, let me know. Thanks!