Simulated data |$D_{\rm 1}$| (source = |$s_{\rm 1}$|⁠, |$P_\mathrm{ f}$| = 12 per cent, i = 90 deg; left) and |$D_\mathrm{7}$| (source = |$s_{\rm 2}$|⁠, |$P_\mathrm{ f}$| = 12 per cent, i = 45 deg; right) at the lowest frequency channel, as an example. From left to right: the input source, the lensed images, the Faraday-rotated lensed images, and the corresponding dirty images for the Stokes parameters |${\boldsymbol {I}}$| (top row), |${\boldsymbol {Q}}$| (middle row), and |${\boldsymbol {U}}$| (bottom row).