It would be neat to see plywood (especially Baltic birch, or something with many plies) as a simulation material in order to see how the light/dark alternating plies create visually interesting patterns as a function of depth, for example with v-carve or ball endmills.
Outer plies in Baltic birch plywood are typically about 0.75 mm, and inner plies are about 1.5 mm, so the number of plies could be programmatically determined from the user-specified thickness. Something like, n = 2 + (t - 2*0.75)/1.5, where t is the thickness in millimeters and n is the number of plies. Then round n to the nearest odd integer and scale the ply thicknesses to fit. 99% of the time, thickness will be 3, 6, 9, 12, or 18 mm – always a multiple of 3 mm to ensure an odd number of plies – but this will also correctly catch/handle the case that someone specifies their plywood as 19 mm (0.75").
Alternatively, you could give the user the option to specify number of plies, but this would violate the Carbide Create minimalist design ethos, hence the programmatic suggestion above.
The programming effort would trivially extend to other multi-tone materials like Richlite, two-tone HDPE, PCB blanks, linoleum, etc… but I’m biased in thinking that Baltic birch would be the most interesting.