according to the patent act, a patentable invention is any new and useful art, process, machine, manufacture or composition of matter, or any new and useful improvement in any art, process, machine, manufacture or composition of matter, which would not have been obvious on the claim date to a person skilled in the art or science to which the invention pertains. among the things which are not normally patentable are:

• an improvement to a known device which would be obvious to a person skilled in the art;
• a scientific principal or abstract theorem;
• a recipe, or design; and
• an idea or a process (or the product of a process) that depends entirely on a person's skill and leads to an ornamental effect.