Bear with this grainy video. It is shot in low light with a simple camera. The video documents two women making tortillas on a clay griddle (a comal) fired with branches from masa (dough) that is prepared from nixtamal (whole corn kernels boiled with lime (cal in Spanish) and ground on a grindstone (matate). The nixtamal has already been ground into masa by the time the film opens but you see the dough on the matate. The tortillas are being formed by being slapped between two hands AND in a separate technique by being placed on the bed of a metate over a piece of thin plastic and then slapped into shape. It is not clear in this video but the comal will be made of terra cotta and coated with a layer of whitewash which is lime and water.

https://www.youtube.com/watch?v=9JbZuAS_h_k&feature=related