x=0{0<y<4}
x^2+y^2=4{0<x}{0<y}
(x-3.5)^2+(y-1)^2=1^2{1<y}
(x-3.5)^2+(y-1)^2=1^2{0<y<1}{2.5<x<3.5}
y=1{2.5<x<4.5}
x=5{0<y<4}
x=5.5{0<y<4}
(x-7)^2+(y-1)^2=1^2
x=-0.25y+11{0<y<2}
x=0.5y+11{0<y<1}
x=-0.5y+12{0<y<1}
x=0.25y+12{0<y<2}
(x-14)^2+(y-1)^2=1^2
(x-17.5)^2+(y)^2=2^2{0<y}{x<17.5}
x=18{0<y<4}
(x-20.5)^2+(y)^2=2^2{0<y}{x<20.5}
x=20.5{0<y<4}