This is a module for doing integer arithmetic in arbitrary base representations. A representation, or "flex", is determined by what symbols you use for +, -, and the digits. The base that you are working in is the number of digits you use to represent your numbers. Given a flex it can do the following: o Convert string representations of numbers to a convenient internal form for calculations as needed. o Convert from one internal representation to another, transparently changing bases as required. o Write the internal representation back to a string. o Handle large integer arithmetic. A sample use would be to write 128 bit MD5 hashes using whatever set of characters you want.