I'm a bit conflicted. On one hand, it is a sin that it still hasn't been built! And it must be powered by a literal steam engine! On the other hand, Babbage

I'm a bit conflicted. On one hand, it is a sin that it still hasn't been built! And it must be powered by a literal steam engine! On the other hand, Babbage never really finished the Analytical Engine. It was always in pre-alpha. In a sense, there is no Analytical Engine. Only a lifetime of sketches for various parts and extensive commentary on how the various parts might fit together. An actual implementation requires making a lot of hard decisions, and basically inventing a fair bit as well. It's clear the Plan 28 folks appreciate all this, of course. They've appropriately started with a complete review of the literature: > With the first-pass inspection of the manuscript archive complete, attention has turned to analysis and interpretation, and organising the findings to aid navigation. Babbage shed versions of the design as it developed in the form of ‘Plans’ – large ‘systems drawings’ which serve as developmental staging posts – the main ones of which number Plan 1 through to Plan 28. This might hint at why Babbage ultimately failed, really. He was a tinkerer and he didn't commit to a design. It was always provisional. When he ran into a minor hitch, or had another good idea, he would go back to the drawing board and start over. If he had just committed and scaled up the original, much simpler and fully-designed difference engine he had been contracted for, he might just have got the funding to continue more theoretical and larger-scale work with thinking machines.