Take a look at the office phones and see if they are easy to open up. If they are, then swap the 1, 2 & 3 buttons with the 7, 8 & 9 buttons.
The phone won't look any different to the untrained eye as calculators are arranged this way. However, no-one but you will get a scrap of sense out of this phone
ever again and if you have a clever computerised exchange like we do, a lot of numbers will be interpreted as intructions to divert or redirect calls, causing
disruption out of all proportion to the simple act you have performed. Just one thing - if you have one of those lockets containing your blood group and other
emergency medical details, now is a good time to append a note recording what you've done to the phone. You never know, tomorrow you could be on the floor,
blue and twitching, while one of your mates is trying to get an ambulance from the speaking clock and before you know it your kidneys are living in someone else. Now, won't that be funny!