Twister board designed by Klaudiusz Fatla is a 2019 take on the Trump Card, Motherboard Expansion Card and the ADS card. All these were solutions to mechanical and electrical link between the Jupiter ACE and ZX81 peripherals. To maintain flexibility and programmability the two connecting edges are quite separate.
With the exception of the chip select lines, WE on the ACE and RAM/ROM CS. on the ZX 81, both computers share the same bus albeit in a different configuration. The Twister Board also includes a power indication LED and a reset button.
Many thanks to Klaudiusz Fatla. Twister Board Gerber files.