Vitruvian Man of math
"What's so special about Leonardo da Vinci's Vitruvian Man? With arms outstretched, the man fills the irreconcilable spaces of a circle and a square -- symbolizing the Renaissance-era belief in the mutable nature of humankind. James Earle explains the geometric, religious and philosophical significance of this deceptively simple drawing." Source
More about the Vitruvian man on my site.