The lesson
Show the buyer that every rival offers the same machine, then number your capabilities and spotlight one with a drawing beside the list.
A deck rebuilt by Pitch Unfairly. "You have seen every war engineer in Italy. Same machine." sits over four identical catapult sketches labeled Proposal A to D, stamped "In common use". A ten-item list follows, headed "Ten capabilities. Nine of them win wars." Another slide reads "Battle record: pending. Portfolio: paintings."
Don't copy the 1482 setting or the mirrored handwriting. Keep the sameness slide and the numbered list with the highlighted item drawn beside it.