You need to set Module.wasmBinaryFile so that SSIMULACRA knows where to find it. And I attached the WASM file to the notebook since your server doesn’t currently set CORS headers (and also because it makes the notebook more self-contained). Lastly, rather than relying on SSIMULACRA to set the FS global, I just attach that global to the ssimulacra object, so that the cell can define a single thing that has everything you need to use it.