  This paper presents a computer program, written in Maple, that allows a user
to simulate certain aspects of Shor's quantum factoring algorithm on a desktop
or laptop computer. The program does not simulate the unitary operations
carried out by a quantum computer but does faithfully mimic its output at the
crucial "readout" step of the order-finding process. The program reqires only
two inputs from the user - the number to be factored (which can be up to 10
digits long) and the number of qubits to be used in the factoring (for which a
helpful hint is given). The program then returns a detailed history of all its
attempts at factoring the number, beginning with its various unsuccessful
attempts and ending with the final successful attempt that leads to the correct
factors. The structure of the simulation is described, a typical output
produced by it is shown, and the factors limiting its performance are
discussed. The purpose of this simulation is to provide the user with some
"hands-on" experience of how quantum factoring works on integers somewhat
larger than can be handled by today's quantum computers.
