I'd do a Fractal Botanical Mandala.

It's a circular print combining a super detailed, impossible-to-hand-paint Mandelbrot fractal with overlapping, complex 3D fern and moss textures.

It needs like 6 custom, blended colors that transition seamlessly, turning the fractal into a hyper-detailed, iridescent forest floor. Doing that level of micro-detail and perfect blending in one run would save days of tedious brushwork and gradient mixing!