When visiting Bath[1] in UK (mentioned in the article), I learned the Romans used a clever contraption, the "three legged lewis", to lift heavy stones[2].
Referring to the diagram[3] on Wikipedia, a concave hole is first cut into the stone. Parts 1 and 2 of the lewis are inserted, one at a time. Inserting part 3 between 1 and 2 results in all three locking into place. A pin and ring at the top keeps the 3 parts from separating.
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