I'm embarrassed to show my attempt at converting this. I'm having trouble with the evaluate-sequence part. I'm reading and writing a PDF. Would someone be so kind in showing the best way to do this as I am not getting an eligible document. I believe I'm not correctly applying the cloned image.
convert $f -colorspace gray \( +clone +noise Random -threshold 99% -negate -blur 0x5 -level 97.5%,97.5% \) -evaluate-sequence min -blur 0xecho $RANDOM %2 +1 | bc` -level 25%,75% -rotate -0.echo $RANDOM %10 +1 | bc -sharpen 0x3.0 -blur 0xecho $RANDOM %2 +1 | bc -level 10%,90% -rotate -0.` echo $RANDOM %10 +1 | bc` -sharpen 0x1.2 -colorspace gray