For me I think that comes to what kind of mechanics the magic itself follows, which might not be a direction you want to veer into. But off the top of my head consider if the magic allowed the punchcards to gain or heal holes in response to the outcome of the computation. This would then allow self-modifying code which then leads nicely towards the symbolic (rather than numeric) calculations, which can then go to predictions of the future (perhaps the intended goal of the magic-designer) but also towards artificial intelligence (perhaps not exactly the goal and a plot twist).