The process for making gray begins by mixing blue and red pigments in more-or-less equal proportions to produce purple. Use more blue to keep the mixture cool and more red if you want a warm color. Adding yellow pigment turns the paint gray, and the more yellow you use, the lighter the mixture will become.
The cave paintings are found mostly in mountains in the present-day Mexican state of Guerrero. The Olmecs created mainly sculptures out of basalt. The Mayans made sculptures out of stucco and created pottery out of clay.
