NTSC (Twice) Pencil stands for Never The Same Colour Twice. It's an ordinary looking pencil, but inside the wooden shaft the lead has been totally modified to become a series of colours delivered in an unpredictable order.
This means that you might start drawing or writing in red, but a short time later that lead is worn down and the blue one starts. The amount of drawing distance allocated to the various colours, along with the order in which they emerge is total random and unique to each pencil.
For example: a red line may be drawn that is several feet long then suddenly it changes to yellow for an inch, then back to red again.
NTSC Twice Pencil has no real practical purpose other than to amuse/aggravate/entertain. This is why it's here and not on the list of essential items required to carry out brain surgery or quantum physics.-- xenzag, Dec 16 2023 My sister had a pencil with a single multicolour lead. This would be about 40 years ago. I'm still jealous.-- pocmloc, Dec 16 2023 (+) Now tell us how we can do it with ink ...-- normzone, Dec 16 2023 Yeah, these exist already. They're not as fun as you'd think.-- Loris, Dec 16 2023 Well, THAT sums up a great deal of the consumer experience!
Okay, I'm thinking about hieroglyphics now ...-- normzone, Dec 16 2023 I think that which I have described doesn’t exist. There are coloured pencils but not with randomly allocated colours or variable capacity of line lengths.-- xenzag, Dec 16 2023 True. (+)-- 2 fries shy of a happy meal, Dec 17 2023 Yes on reflection my sister's pencil had the different colours laminated radially, so that the colour changed as the pencil rotated. It was possible to use anti-rotational skills to write consistently in one colour (until the lead wore away allowing other colours to contact the paper despite maintaining the same orientation). That part of it at least would be a functional mimic of the idea as posted.
I also want to pedantically object to the title. "a red line may be drawn ... then suddenly it changes to yellow ..., then back to red again// so you have had red twice, violating the specification given in the title.-- pocmloc, Dec 17 2023 Ah - one red is alizarin crimson and the other rose malmaison. There are many reds.-- xenzag, Dec 17 2023 That's all right then, carry on.-- pocmloc, Dec 17 2023 If your colors don’t come out correctly you can always call a PAL to help fix it.
Also, the National Transportation, Safety, and Commerce agency may have a trademark dispute here.-- minoradjustments, Dec 19 2023 random, halfbakery