Art within Interpolations

As it happens many times, I came across a beautiful image during my work. This is the difference between two interpolated CT images using different window functions (Lanczos and Welch) in a Windowed Sinc Interpolator. The cold areas indicate that the 'colors' of the resulting images were almost the same, while warm areas indicate larger differences.  In general you can see a kind of a grid, which is an aliasing effect (at least, that's my theory...).