A marketplace is a good place to find those retro plastic keychain fobs with a Buick at one pov and Betty Grable at another. Agora IS an ancient art process to wit (which at this day is to Google), an application of pigment and wax to? perhaps amphorae.
If you were making images on the two opposing sides of parallel "furrows" made by an engraving chisel, you'd stipple or "dimple" one image onto all the facets which are the north side of the furrows; the other image on all the facets which constitute the south sides of the furrows just as CZ says. To view, you would have to change your pov as with the novelty keychain. Not as easy to rotate a gun action as it is a keychain but no great hardship in the interest of capital-A Art.
jack
