Saturday Mac riddles 87

Here are this weekend’s riddles to entertain you through whatever you’re now allowed to do.

1: Unique among all the others, I’m the one you only press when you don’t want me. Which am I?

2: My first is in Macintosh but not in Mac, and my second is exactly that. Together they were security for the future, but are now a thing of the past. What am I?

3: Conceived almost thirty years ago for interactive TV, I was originally named for a tree, and am intended to work anywhere. What am I?

I will post the answers first thing on Monday morning.

Please don’t post your answers as comments here: it spoils it for others.