Because two arms would just look ridiculous

The print might be an artist's impression of a multi-dimensional universe - hence the purple and yellow cubes (always an attractive colour combination), several Higgs bosons (oh, they were on this dress all the time), and the tracks left by protons as they whirl around the Large Hadron Collider.

A tough brief, but well done scientific illustrator!  My retinas will probably reattach themselves shortly.

£22, River Island.  At least this ugliness comes cheap.