Perhaps not many of you know the C-One (Commodore One). This computer is unique because it’s a reconfigurable computer. This means that in can “morph” into many different computers. To say it in simple words it’s somewhat like an emulator, but in hardware, more accurately it’s reimplementation of other chips in FPGA (field programmable gate arrays) chips. In other words the main chips of this machine can be programmed to behave as other chips.
So when you boot the computer the main chips are re-programmed with the cores (FPGA programs) and can function as other computers like the C64, VIC-20, plus/4, TI-99/4a, Atari 2600, Atari 400/800 series, Sinclair Spectrum, ZX81, Schneider CPC and many more or an entirely new computer not yet known by the human beign, all this without even opening the computer case.
AFAIK the only cores available are the C64, CPC 464 and CPC 6128. And today I found the VIC-20 core here.