You can leave the TI graphing calculator at home thanks to this web-based TI-83 and TI-84 emulator. As with pretty much all emulators, this depends on a ROM image from the actual hardware to work.

The team made extensive use of the ArTICL library which allows graphing calculators to interface with microcontrollers like the MSP432 that they used, and drove the whole thing with a classic TI-84.