Abstract: In a device using an impregnated paper with a chemically reactive marker, the device includes a box-like housing having a translucent planar surface with light projected from within the box onto the rear side of the surface. A paper impregnated with an indicator dye resulting in an opaque paper is placed on the surface. Marker pens having substance chemically reactive with the indicator dye are used to mark the paper. The chemical reaction between the marker solution and the coating renders the so-marked areas translucent for passage of light through the paper in the region so-marked. Transparent dyes are utilized in the markers to combine with the color of the indicator dye to form a third color which is a combination of the two colors.