Examples from literature

• I may now frame the idea of a mathematical circle, in which all diameters are precisely equal, in express contrast to the series of ellipses, with very unequal diameters, which the floundering hoop has illustrated in its career. 
• The center of an ellipse is within the curve. 
• The course was in the shape of an ellipse, with rather sharp turns at either end, where the contestants, if they did not want a spill, or a bad skid, must slacken their pace. 
• The ellipse and the parabola have no asymptotes. 
• Their ellipses elongate and flatten again to the semblance of circles.