You're looking for a New World PowerMac. If you hold down the right key combination while turning it on, you will land in Open Firmware. While quite different

You're looking for a New World PowerMac. If you hold down the right key combination while turning it on, you will land in Open Firmware. While quite different from BASIC, it is a programming environment similar to the olden days. And is the Rasberry Pi comment a reference to RISC OS, with its ability to access BBC BASIC by pressing F12 and typing a quick command?