Prime the wall with two coats of off-white latex paint, and allow it to dry. Use a pencil and ruler to mark off squares that suggest stone blocks. They can be any size appropriate for the surroundings, but 8" by 16" is the standard size of real blocks.
To add a warm undertone to the wall, apply a limestone-colored wash of latex paints. Mix small amounts of taupe and yellow paint, and thin with water to the consistency of thin soup. Brush the wash freely in all directions, and rub it into the surface with a cloth. Don't strive for a carefully painted finish.
Use three shades for shadowing: taupe for a dark shade, off-white for a medium shade and white for highlighting. Mix each color with water to a watercolor consistency. To make light appear to come from one side, stipple the colors onto the wall in the following pattern: the darker color on the left, the medium in the middle and the light on the right side. Freely dab or stipple the color on the wall, rubbing the color into the surface as you work.
Thin a mixture of creamy taupe and white with water. Using a brush with long bristles, paint the mixture over the pencil lines. The lines should show through to create the look of shadows between the blocks.