Verify the basic operation of the feSpecularLighting element. The test shows four rows of 3 images. Each rows tests a different aspect of the filter and shows the result of the filtering operation.

The first row shows the result of varying the surfaceScale attribute. The second row shows the result of varying the specular constant (ks) attribute. The third row shows the result of varying the specular exponent (np) attribute. The last row shows the result of varying the lighting-color property.

The rendered picture should match the reference image.