Question: Animate two phase portrait in one

Hi everyone,

I have this differential equations:

gamma1:=1;gamma2:=1;

l:=t->sqrt((x1(t)-x2(t))**2+(y1(t)-y2(t))**2);
2 2
l := t -> sqrt((x1(t) - x2(t)) + (y1(t) - y2(t)) )

DE:=[diff(x1(t),t)=(-1/(2*Pi))*gamma2*(y1(t)-y2(t))/l(t),diff(y1(t),t)=(-1/(2*Pi))*gamma1*(x1(t)-x2(t))/l(t),diff(x2(t),t)=(-1/(2*Pi))*gamma2*(y2(t)-y1(t))/l(t),diff(y2(t),t)=(-1/(2*Pi))*gamma1*(x2(t)-x1(t))/l(t)]:

I want to draw the phase portraits (x1(t),y1(t)) and (x2(t),y2(t)) in the same plot and animate in time to see how is the trajectory.

Here is what I did:

display(phaseportrait(DE,[x1(t),x2(t),y1(t),y2(t)],t=0..50,[[x1(0)=1,x2(0)=-1,y1(0)=1,y2(0)=0]],scene=[x1(t),y1(t)],title=`Asymptotic solution`,colour=magenta,linecolor=[gold],animatecurves=true),phaseportrait(DE,[x1(t),x2(t),y1(t),y2(t)],t=0..50,[[x1(0)=1,x2(0)=-1,y1(0)=1,y2(0)=0]],scene=[x2(t),y2(t)],title=`Asymptotic solution`,colour=magenta,linecolor=[gold],animatecurves=true));

My problem is that it draws only one phase portrait and not both.

Does someone have a hint on the issue?

Thanks.