.PS
cct_init

# Usual defs...
qrt=dimen_/4;
hlf=dimen_/2;
dim=dimen_;

E1:ellipse width 0.2*dim height 0.1*dim 
E2:ellipse same at E1.center+(0,-dim)
# paint white over the top of the bottom ellipse...
box invis fill 1 width 0.2*dim-lthick height 0.1*dim with .c at E2.n
line from E1.e to E2.e
line from E1.w to E2.w
dimension_(from E1.w to E2.w,-5mm__,$d\ell$,3mm__)
line dotted from E1.e+(dim/2,0) to E2.e+(dim/2,0)
"$I$" at last line.center+(dim/10,0) ljust_

"\tiny Ideal" at (dim,-1.5*dim)
.PE