  We study generalized regular bent functions using a representation by bent
rectangles, that is, special matrices with restrictions on rows and columns. We
describe affine transformations of bent rectangles, propose new biaffine and
bilinear constructions, study partitions of a vector space into affine planes
of the same dimension and use such partitions to build bent rectangles. We
illustrate the concept of bent rectangles by examples for the Boolean case.
