Working RPN requires a substantial increment in intellectual capacity compared to applying a sequence of elementary operations to an accumulator. An operand co

Working RPN requires a substantial increment in intellectual capacity compared to applying a sequence of elementary operations to an accumulator. An operand consumed by a given RPN operation can be quite distant from it in the syntax, such that it's not obvious which one. A valid RPN expression could consist of an initial sequence of N operands, where N is limited only by stack depth, followed by a sequence of N-1 operators to decimate the operands.