% parabolaonthestage.mp % L. Nobre G. % 2014 input featpost3Dplus2D; Spread := 30; f := (5,3,2); beginfig(1); numeric i, li; li = 50; setthestage( 18, 10 ); draw for i=-li step 0.25 until li-0.25: rp((5-(i**2),i,0))... endfor rp((5-(li**2),li,0)) withcolor blue withpen pencircle scaled 3pt; endfig; end.