The RPN Graph Calculator is a reverse polish notation calculator. Reverse Polish notation (RPN) is a mathematical notation in which every operator follows all of its operands, in contrast to Polish notation, which puts the operator in the prefix position. It is also known as postfix notation and is parenthesis-free as long as operator arities are fixed (wiki).
This RPN Graph Calculator also features a limited graphing capability whereby algebraic functions that are input can be plotted (requires device to be rotated into landscape mode to access).