import geometry; size(10cm,0); currentcoordsys=cartesiansystem((1.5,1.5),i=(1,0.5),j=(-1,1)); coordsys Rp=currentcoordsys; coordsys Rs=cartesiansystem((-1.5,1.5),i=(-1,0.5),j=(-1,-1)); coordsys R=defaultcoordsys; show("$O$","$\vec{\imath}$", "$\vec{\jmath}$", R); show("$O'$","$\vec{u}$","$\vec{v}$", Rp, xpen=invisible); show("$O''$","$\vec{u'}$","$\vec{v'}$", Rs, xpen=invisible); int n=64; real step=2pi/n; for (int i=0; i