Carvão Quadrilateral
The other day Pat Belew (@OnThisDayinMath) started off his always-fascinating On This Day in Math blog, http://pballew.blogspot.com/, with that great image up top, an oil painting by Aluisio Carvão. I thought it was perfect for dynamicization.
Be sure to check out more geometry inspired art from this great painter.
See more at the Tumblr post: http://mathhombre.tumblr.com/post/66599985878/carvao-the-other-day-pat-belew
More GeoGebra at mathhombre.blogspot.com