The 400 isn’t quite what I had in mind. I was thinking more of a device usable even by the under-10 group, with a simpler and more robust physical design and, crucially, the kind of instant-on, guided programming environment the early home “PCs” had.

With early Sinclair systems, each key on the keyboard would act like modern auto-complete: you would start typing and keywords would appear almost magically. On the BBC Micro, you powered on and heard the trademark beeeeep-beep and were instantly presented with a prompt where you could start typing a program or other commands. Everything in those systems was geared towards immediate responses and inviting you to start programming them straight away.

It's a very interesting device in a very Spectrum-like form factor. It also has its limitations, much like the Spectrum itself - you're not going to code comfortably in resource-intensive languages with it.