Unit circles in R^2 using different metrics

>	with(plots):

>	ball1:=implicitplot( abs(x)+abs(y)=1,x=-1..1,y=-1..1,thickness=2,color=plum,numpoints=1000):

>	ball2:=implicitplot( x^2+y^2=1,x=-1..1,y=-1..1,thickness=2,color=red):

>	ball3:=implicitplot( abs(x^3)+abs(y^3)=1,x=-1..1,y=-1..1,thickness=2,color=green):

>	ball4:=implicitplot( x^4+y^4=1,x=-1..1,y=-1..1,thickness=2,color=blue):

>	ball5:=implicitplot( abs(x^5)+abs(y^5)=1,x=-1..1,y=-1..1,thickness=2,color=cyan):

>	ballhalf:=implicitplot( sqrt(abs(x))+sqrt(abs(y))=1,x=-1..1,y=-1..1,thickness=2,color=pink,numpoints=1000):

>	ballthird:=implicitplot( root(abs(x),3)+root(abs(y),3)=1,x=-1..1,y=-1..1,thickness=2,color=brown,numpoints=1000):

>	ballinfinity:=implicitplot( max(abs(x),abs(y))=1,x=-1..1,y=-1..1,thickness=2,color=black,numpoints=10000):

>	display(ballthird,ballhalf,ball1,ball2,ball3,ball4,ball5,ballinfinity);

>