.PS cct_init # Usual defs... qrt=dimen_/4; hlf=dimen_/2; dim=dimen_; L1:line up_ 2*dim arc cw from L1.start to L1.end rad 2*dim ;right_ C1:circle radius dim with .c at L1.center+(2*dim,0) C2:circle dashed radius 0.7*dim filled 0.9 at C1.c arrow from C1.c to C1.se ; " $r$" ljust_ below_ move to C1.ne then up_ hlf then right_ hlf {" $A_p=\pi r^2$" ljust_} line -> to C1.ne "$A_e= \frac{G\lambda^2}{4\pi}$ " rjust_ below_ at C1.sw+(-hlf, -hlf) line -> dashed to C2.sw "\tiny ApertureEff" at (4*dim,-hlf) .PE