Whether you're a Mac or a PC (or a bit of both) this witty concept design has something for all-comers, with the clever design idea to create real-world versions of the calculators found in operating systems.

Just a concept at this stage, although we reckon with real product potential, the Mintpass designer has managed to capture the individual characteristics of the XP calculator and Apple's more metallic option perfectly.

Of course, if they were real world products the Mac version would be over-priced - and likely boast a non-replaceable battery - while the Windows version would crash often and may well come with an over-friendly paperclip as a free gift.