x = var('x')
p1 = parametric_plot((cos(x),sin(x)),(x,0,pi),color='red')
p2 =parametric_plot((1/2-(1/2*cos(x)),1/2*sin(x)),(x,0,pi),color='black')
p3 =parametric_plot((1/2*cos(x)-1/2,1/2*sin(x)),(x,-pi,0),color='red')
p4 = parametric_plot((cos(x),sin(x)),(x,-pi,0),color='black')
p5 = parametric_plot((1/2-(1/8*cos(x)),1/8*sin(x)),(x,-pi,pi),color='black')
p6 = parametric_plot(((1/8*cos(x)-1/2),1/8*sin(x)),(x,-pi,pi),color='red')
show(p1+p2+p3+p4+p5+p6,figsize=(4,4), aspect_ratio=1,axes=true)
