 (A) {A};   \draw[dashed]     let \p0 = ($ (A.after bottom) - (A.before bottom) $),         \n0 = {0.0*veclen(\x0,\y0)},         \p0 = ($ (A.bottom) - (A.after bottom)!.0!(A.before bottom) $),         \n0 = {veclen(\x0,\y0)