While my brother was here, he showed me something he'd found in a charity shop, and asked "Do you remember this book?"
"Not even slightly..." I said, picking it up and looking at it. "OH, GOD, YES!" I exclaimed after opening it up and seeing the Computer Card and Word Displays inside. It's only the best book ever, 'Hello Sam' by Heinz Kurth!
It's about a Solar Automatic Man called Sam, and you communicate with him like this:
Take the Computer Card that comes with the book and put it on top of the appropriate coloured word...
And hey presto, you're having a conversation! Such an ingenious idea, and I really loved it when I first read the book. There's an adventure involving Sam's Booster Box, that makes things grow bigger. And it ends with Sam telling us he's going to the sea for a holiday and that perhaps he'll see us there, but I don't know if there was ever a sequel. I don't know what happened to our original copy of this book, either - we weren't exactly ones to throw things away, but I don't remember seeing it after I was eight or nine. Impressively, this nearly-30-year-old copy still has the Computer Card with it - not necessary, since the book cleverly includes a template for you to make a replacement, but still cool!