Shape borrowing is using shapes that you have found to design items that you can use. For example, you can use a square to design a bookshelf. If you do not use shape borrowing, designing the item may be harder as you do not know what to design an item after.
S.C.A.M.P.E.R is a way of improving the design of an object. S.C.A.M.P.E.R is an acronym for:
Substitute - Changing a part of the design to another part of an product to improve the overall design.
Combine - Putting together a few good aspects of a few designs to create a new and improved design.
Adapt - Finding out about what consumers want and adapting your design to their needs.
Modify - Changing a part of the design to another part to improve the design or the use.
Put to other use - Your designed product may not be useful for its designed purpose, but it may work as another object.
Eliminate - Removing useless parts of your design to improve the overall design.
Rearrange and reverse - Switching parts of your design around to improve the performance or the design of the product.