import geometry; size(8cm,0); currentcoordsys=cartesiansystem((2,1),i=(1,0.5),j=(-0.25,.75)); show(currentcoordsys); point A=(1,1); dot("$A$",A,S,red); real R=2; circle C=circle(A,R); draw(C,Arrow); /**/ ellipse el=xscale(2)*C; draw(el,blue,Arrow); // /**/ ellipse el=xscale(2,A)*C; draw(el,red,Arrow);