A blonde, a brunette and a redhead all work in the same office building, and everyday they have lunch together down the road at a cafe. On one occassion they are coming back to work and they see a small puddle of white-ish liquid on the foyer floor. The redhead exclaims "oh that LOOKS like semen!" and they all agree. The brunette leans down and smells it and exclaims "And it SMELLS like semen". The blonde leans down and licks it and then thinks thoughtfully "Well at least we know its none of the guys in our office building!!"