Bathtub fitting standard external space while affording larger floor area and enclosed volume

A bathtub comprising:

• substantially vertical back and front walls, first and second side walls, and a flat bottom wall, all of said walls being of rigid material,
• entry and egress of a user being over said front wall, said back wall abutting or is embedded in a bathroom wall;
• said bottom wall extending to a rear, vertical surface of said front wall;
• said back bathroom wall having wall tiles thereon, said back wall of said bathtub having a top edge sufficient in thickness to accommodate bottom edges of said wall tiles, when said back wall of said bathtub abuts, or is embedded in, a bathroom wall;
• wherein said rear wall comprises a combination of a front rear wall portion of about one quarter inch in thickness, and a hollow air space portion of about three quarter inches extending behind said front rear wall up to the surface of the bathroom wall, to accommodate tile and tile grout therebetween;
• side bathroom walls abutting said end walls of said bathtub, leaving access and egress only over said front wall of said bathtub;
• said front wall in contact with said bottom wall is rounded at the intersection thereof;
• and,
• each of said bathtub walls having a thickness greater at the bottom thereof than of the top thereof to provide a slightly sloped surface for drainage or for easy removal of the bathtub from a mold.