I can't believe it took a couple days before I remembered I could do radial symmetry on Photoshop. That really helped create some of the more interesting designs like this swirling one, though I didn't too far.
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The cogs of the Cogwork Citadel are magically enchanted to repel all sorts of damage to the moving fortress. The occasional cog that falls off the citadel are quickly scavenged and repurposed as deflecting shields.
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Brasstion Cog
Shield, very rare
While you wield this shield, whenever you would take 10 or less damage from a single source, the shield reduces that damage to 0.
Legendary Variant. This shield prevents damage from a single source that is 15 or less instead of 10 or less.