2.7.1.1. Demo 1

Demo

1. Generate an image with <Toolbox> -> Xtns -> Script-Fu -> Patterns -> "3D Truchet" .
2. Duplicate the layer using <Layers> -> Duplicate Layer .
3. Render a nice gradient on the lower layer.
4. Generate an alpha on the upper layer by using <Layers> -> "Add Layer Mask..." .
5. Select the paintbrush tool and paint black strokes on the alpha of the upper layer.
6. Switch to a grey colour and paint grey strokes.
7. Finalize the Layer's Mask using <Layers> -> "Apply Layer Mask"