Accidental Turing completeness brings to mind the Zuse Z3 computer discussed recently. This 1941 system only supported fixed sequences without branching, but it

Accidental Turing completeness brings to mind the Zuse Z3 computer discussed recently. This 1941 system only supported fixed sequences without branching, but it was shown [1] to be Turing complete if you use weird tricks. The point is that it is fairly easy for systems to unexpectedly be Turing complete. On the other hand, the language built into Bitcoin [2] was deliberately designed not to be Turing complete. This avoids problems in deciding if a transaction is valid or not. [1] http://www.inf.fu-berlin.de/inst/ag-ki/rojas_home/documents/1997/Universal_Computer.pdf http://www.inf.fu-berlin.de/inst/ag-ki/rojas_home/documents/... [2] https://en.bitcoin.it/wiki/Script https://en.bitcoin.it/wiki/Script