Texas does not specifically say they have to be crossed. But the requirement almost makes it mandatory.
(2) The two safety chains will be of equal length, long enough to permit free turning of the vehicles without placing stress on the chains, and attached to the towing vehicle equidistant right and left of the point at which the vehicles are connected. The safety chains must be connected to the towed and towing vehicles and to the tow-bar in a manner which prevents the tow-bar from dropping to the ground in the event it fails or becomes disconnected. In no event will the safety chains be allowed to contact the road surface during movement of the vehicles.
(I put the specific text in bold)