This month's tip centers on an alternative view of functions. Instead of perpendicular axes for domain and range, we explore parallel axes. This idea has been around for a while (see the references in Bridger and Bridger ( and in the “Surfing Note”), but we hope to breathe new life into this fascinating representation of functions with two easy-to-use programs for the TI-83 Plus. We provide an introduction to mapping diagrams (also called function diagrams) and the code for one program to produce them using the TI-83 Plus. Information about the second program will be given in “Technology Tips” in May. Both programs are available electronically, so users do not have to type the programs into their calculators.