A quick, one-liner riddle

I would like feedback on this riddle I made up. I would classify it with a moderately difficult rating, but I could be wrong.

Of tiny little planks from end to end when told are sharp and flat.

When moving: forward or not at all, and family to us all, at that!

Please let me know how easy it was to solve, and if you needed the hint(s).

HINT 1

plank = planck

HINT 2

family = relative

• Since this riddle is so short, it seems that most of the 'difficulty' for solving this riddle would be having them guess what you want, rather than what fits. With less information given, there becomes more possible answers. – Mark N May 29 '15 at 16:18
• @MarkN I've added a second line which narrows the focus. Thanks for the advice! – ridthyself May 29 '15 at 16:29
• How about better grammar? That might help. It's hard to understand what you're driving at. I know it's a riddle, but the words don't actually make any sense, especially the last sentence - "at that!"??? – Bohemian May 29 '15 at 16:40
• @Bohemian "at that" is a common idiom meaning in addition to, besides. "it was a long wait, and an exasperating one at that" – ridthyself May 29 '15 at 16:46
• I think your two hints should be incorporated into the riddle itself (easy enough to do) to make it more doable and to ensure the solution is unique. – Rand al'Thor May 30 '15 at 21:41

Is it

Light

Of tiny little planks from end to end when told are sharp and flat

A planck length is the minimum distance that light travels

When moving: forward or not at all

Light travels in tranverse wave

and family to us all, at that!

Reference to Einstein's theory of relativity

• But your answer always moves at a constant speed regardless of the frame of reference? – Hackiisan Aug 29 '15 at 5:27

It's a...

Piano (or possibly referring more specifically to "ebony", as in the black keys)

Because it's referencing

Sharp and flat notes are played by playing the "black" keys on a piano, which can be thought of as tiny little boards that run all along the piano (end to end).

• I fear these answers might be better than the one I had in mind, this one in particular. I changed "boards" to "planks" to steer you in the right direction. – ridthyself May 29 '15 at 16:08
• This is the first thing that came to my mind as well. :) – LindaJeanne May 29 '15 at 18:56

Its clearly ...

An assorted cheddar cheese tray

Because ...

It has a bunch of sharp cheddar cheese cut into flat squares all lined up from end to end. And there are different types of cheddar that are related to each other because they are all cheese.

• HAHAHA I love it! Sorry, no. Cheddar cheese is able to move in more directions than "forward or not at all". – ridthyself May 29 '15 at 17:00
• Unless you are talking about how the cheese advances through time :) – default May 29 '15 at 17:34

quantum relativity

Here's how I reached it:

"Plank" is a pun on Max Planck - the father of quantum mechanics
"tiny little planks" refers to the planck length - the quantum of space
"when told are sharp and flat" more or less means that when observed, the wave/particle duality condenses to either a "flat" wave or a "sharp" particle
family = relative(-ity) (from hint)
movement is relative. being stationary is relative.

I think you could afford to be less obtuse.

• I would like to judge your answer at the correct one, but ironically, (given your suggestion that I be less obtuse) your answer is too broad. narrow it down a bit, and it's yours. – ridthyself May 29 '15 at 17:50

I think the answer is a

Book

Because:

The little boards represent the pages of the book, which is a stack of pages, from beginning to end. The single sheets are sharp (you can hurt your finger with them) and flat.

• Wow, that's actually very good. I would accept that as a secondary answer, because it fits so well. But I think the answer I had in mind fits a little bit better. – ridthyself May 29 '15 at 15:57

It could be a:

Song

Because:

Tiny little boards could be referring to the five lines on the staff, and when the notes of a song are "told" they can be sharp or flat.

• ah yes, but they are sharp AND flat. – ridthyself May 29 '15 at 16:00
• To be fair, all sharps are also flats (G-sharp is the same note as A-flat). – Bailey M May 29 '15 at 16:08
• @BaileyM - To be pedantic, that's only sort of true. There is actually a slight difference between a G-sharp and an A-flat. Instruments like the piano average the two as a compromise, but wind and string players as well as singers can achieve a more "perfect" harmony by being aware of the difference. – Darrel Hoffman Mar 20 '16 at 20:05