import graph; size(0,100); real r=1; real h=3; yaxis(dashed); real m=0.475*h; draw((r,0)--(r,h)); label("$L$",(r,0.5*h),E); real s=4; pair z1=(s,0); pair z2=z1+(2*pi*r,h); filldraw(box(z1,z2),lightgreen); pair zm=0.5*(z1+z2); label("$L$",(z1.x,zm.y),W); label("$2\pi r$",(zm.x,z2.y),N); draw("$r$",(0,m)--(r,m),N,red,Arrows); draw((0,1.015h),yscale(0.5)*arc(0,0.25cm,-250,70),red,ArcArrow);